The DOI matches its Crossref record; 33 of the 35 references it cites were found in a registry or an index; none of the 21 sources its claims cite is checked for support yet.
Nicotine, cotinine, and anabasine inhibit aromatase in human trophoblast in vitro.
Open accessAbstract
Epidemiologic studies suggest that women who smoke have lower endogenous estrogen than nonsmokers. To explore the possible link between cigarette smoking and decreased endogenous estrogens, we have examined the effects of constituents of tobacco on estrogen production in human choriocarcinoma cells and term placental microsomes. In choriocarcinoma cell cultures, nicotine, cotinine (a major metabolite of nicotine), and anabasine (a minor component of cigarette tobacco) all inhibited androstenedione conversion to estrogen in a dose-dependent fashion. Removal of nicotine, cotinine, and anabasine from the culture medium resulted in the complete reversal of the inhibition of aromatase. In the choriocarcinoma cell cultures, a supraphysiologic concentration of androstenedione (73 microM) in the culture medium blocked the inhibition of aromatase caused by nicotine, cotinine, and anabasine. In preparations of term placental microsomes, nicotine, cotinine, and anabasine inhibited the conversion of testosterone to estrogen. Kinetic analysis demonstrated the inhibition to be competitive with respect to the substrate. These findings suggest that some nicotinic alkaloids directly inhibit aromatase. This mechanism may explain, in part, the decreased estrogen observed in women who smoke.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In the chorio- carcinoma cell cultures, a supraphysiologic concentration of an- drostenedione (73 ,M) in the culture medium blocked the in- hibition of aromatase caused by nicotine, cotinine, and anabasine.”
- Also stated in: § Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures · plain
“when the culture medium contained 73 1tM androstenedione, 30 ,M nicotine produced no inhibition of estradiol accumulation (Fig. 4).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Also stated in: § Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Aqueous extracts ofsmoke inhibited androstenedione conversion to estradiol in a dose-dependent manner (Fig. I A).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofaqueous extracts ofcigarette smoke on estrogen accumulation in choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Examination of the timecourse of nicotine inhibition of estradiol accumulation demonstrated that nicotine inhibited es- tradiol accumulation at the first timepoint examined, 1 h (Fig. 3).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Strength:boosted· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“At con- centrations up to 150 ,uM, nicotine, cotinine, and anabasine did not alter cell number at the end of an 8-h incubation.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In contrast, at concentrations in the range offoot_2 mM, carbamylcholine, succinylcholine, hexamethonium, and decamethonium did not inhibit estradiol accumulation (Table III).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In contrast, when the culture medium contained 73 1tM androstenedione, 30 ,M nicotine produced no inhibition of estradiol accumulation (Fig. 4).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Nicotine in- hibited the accumulation of estradiol in a manner comparable to that observed in incubations of intact cells (data not shown).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In these three separate experiments the Kis for cotinine inhibition of aroma- tization were 15, 36, and 47 MuM (32.7±9.38 MM, mean±SEM) (Fig. 6).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Dialyzed smoke preparations (1,000 mol wt effective pore size) inhibited androstenedione conversion to estradiol in a dose- dependent manner (Fig. 1 B).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofaqueous extracts ofcigarette smoke on estrogen accumulation in choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In choriocarcinoma cell cultures, nicotine, cotinine (a major metabolite of nicotine), and anabasine (a minor component of cigarette tobacco) all inhibited androstenedione conversion to estrogen in a dose-dependent fashion.”
- Also stated in: § Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures · plain
“The addition of nicotine, cotinine, or anabasine to the chorio- carcinoma cell cultures inhibited estradiol accumulation in the media (Fig. 2).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Also stated in: § Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Removal of nicotine, co- tinine, and anabasine from the culture medium resulted in the complete reversal of the inhibition of.aromatase.”
- Also stated in: § Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures · plain
“Removal of nicotine, cotinine, and anabasine from the culture medium resulted in the complete reversal of the inhibition of estradiol accumulation and the return to normal rates of estradiol accu- mulation.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Also stated in: § Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Nicotine, at concentrations as high as 100 MM, did not signifi- cantly alter placental microsomal 17j3-hydroxysteroid dehydrogenase activity (Table V).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Addition of nicotine to placental microsomal preparations elicited a type II cytochrome P-450 difference spec- trum with a broad Soret minimum between 390 and 400 nm and a Soret maximum at 428 nm (Fig. 7).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“50% inhibition ofaromatase was observed at a smoke extract dose between 1 and 5 Ml (1 Ml of aqueous smoke solution represents 0.1% of a cigarette equivalent).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofaqueous extracts ofcigarette smoke on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Kinetic analysis demonstrated the inhibition to be competitive with respect to the substrate.”
- Also stated in: § Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes · boosted
“Dixon plot analysis demonstrated that nicotine, cotinine, and anabasine inhibition of aromatase was competitive with respect to the testosterone substrate (Figs. 5 and 6).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Also stated in: § Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes · boosted
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Progesterone and estradiol were not rapidly metabolized by the choriocarcinoma cells.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“At concentrations up to 30 uM these three compounds did not inhibit progesterone accumulation (Fig. 2).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In the choriocarcinoma cell cultures, the concentration of androstenedione present in the culture medium strongly influenced the degree of inhibition of estradiol accumulation pro- duced by nicotine.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Strength:boosted· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In preparations of term placental microsomes, nicotine, co- tinine, and anabasine inhibited the conversion of testosterone to estrogen.”
- Also stated in: § Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes · plain
“In all preparations of placental microsomes examined, nicotine, cotinine, and anabasine inhibited the conversion of [ 1(,2,3-3H]testosterone to 3H20.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Also stated in: § Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In addition to inhibiting estradiol accumulation in intact choriocarcinoma cell cultures, nicotine also inhibited estradiol accumulation in cell-free preparations ofchoriocarcinoma cells.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“At the highest dose tested, 25 ,l, aromatization was inhibited by 40%.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofaqueous extracts ofcigarette smoke on estrogen accumulation in choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“At all nicotine concentrations tested, the estradiol to estrone ratio exceeded 6:1.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedn = 4Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“when the culture medium con- tained 11 nM androstenedione, 30,M nicotine produced an -50% inhibition of estradiol accumulation.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“150-!LM concentrations of both anabasine and nicotine resulted in a decrease in progesterone accumulation of -15% (Fig. 2).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Removal of the aqueous extract ofcigarette smoke from the culture medium resulted in the complete reversal ofthe inhibition of aromatase, and the return of normal rates of aromatization.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofaqueous extracts ofcigarette smoke on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Androstenedione in concentrations as low as 2 nM resulted in the significant accumulation of estradiol.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Dixon plot analysis demonstrated that nicotine, cotinine, and anabasine inhibition of aromatase was competitive with respect to the testosterone substrate (Figs. 5 and 6).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In all preparations of placental microsomes examined, nicotine, cotinine, and anabasine inhibited the conversion of [ 1(,2,3-3H]testosterone to 3H20.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For example, the addition of 18 nM androstenedione to 200,000 choriocarcinoma cells for 18 h resulted in the detection of 12.6 nM estradiol, 1.26 nM estrone, 25.3 nM progesterone, and <0.2 nM testosterone and dihydrotestosterone in the media at the end of the incubation (Table I).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In contrast to nicotine, cotinine, and anabasine, the cholin- ergic agents-hexamethonium, decamethonium, acetylcholine, succinylcholine, carbamylcholine, and muscarine-did not in- hibit aromatase in the placental microsomes (Table IV).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In these five separate experiments the apparent enzymatic inhibition constants (K,)' for nicotine inhibition of aromatization were 15, 17, 25, 37, and 73 ,M (33±10.6MuM, mean±SEM) (Fig. 5).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The PBS vehicle, in doses up to 30 ,l, did not affect estradiol accumu- lation.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofaqueous extracts ofcigarette smoke on estrogen accumulation in choriocarcinoma cell cultures
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In serum-free choriocarcinoma cell cultures, estradiol and estrone were not detectable (<0.05 pmol/ml) unless androgen substrate (androstenedione or testosterone) was added to the medium.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Maximal estradiol accumulation occurred at androstenedione concentrations between 400 nM and 1 AM.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Strength:plain· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Nicotine inhibition ofestradiol accumulation was linear over the first 8 h of incubation (Fig. 3).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In these two experiments the apparent Kis for anabasine inhibition of aromatase were 2 and 3 MM.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Strength:plain· not yet calibratedn = 2Tests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Lobe- line, at concentrations of 100 MM, produced a 30% inhibition of placental microsomal aromatase.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, anabasine, and cotinine on aromatase activity in preparations ofterm placental microsomes
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Therefore, -10% of the aromatase inhibitory activity of aqueous extracts of cigarette smoke was present in the > I,000-mol-wt fraction.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofaqueous extracts ofcigarette smoke on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIn the paper
“In pregnancy, women who smoke have lower estrogens than nonsmokers (4).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Introduction
What the sources say
- Not checked — no full text of the sourcecites [4] 4. Mochizuki, M., T. Maruo, K. Masuko, and T. Ohtsu. 1984. Effects of smoking on fetoplacental-maternal system during pregnancy. Am. J. Obstet. Gynecol. 149:413-420. source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“In nonpregnant women who smoke, plasma nicotine and cotinine concentrations are in the range of 0.25 and 2 ,M, re- spectively (22)(23)(24).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
What the sources say
- Not matchedcites (22)(23)(24)
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Not matched
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This mechanism may explain, in part, the decreased estrogen observed in women who smoke.”
- Also stated in: § Discussion · hedged
“the in vitro findings reported here may have relevance in vivo.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: The aromatase enzyme system in human granulosa cells is similar to placental aromatase.
- Rests on an assumption: The concentrations of nicotine and cotinine in body fluids reflect their concentrations at the aromatase enzyme site in ovarian or placental tissues.
- Also stated in: § Discussion · hedged
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It is unlikely that the nicotine inhibition of estradiol accumulation observed in the choriocarcinoma cell cultures is due to a”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“In women, androstene- dione concentrations in the circulation ranged between 0.3 nM and 11 nM.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
What the sources say
- Not matchedcites [19] 19. C. F. Chignell, editor. Appleton Century Crofts, NY. 303-350.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes- Not matched
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These results suggest that progesterone and estradiol accumulation in the media correlate well with production.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesNone of the sources cited for this claim have been checked yet.
In the paper
“women who smoke have an earlier age of menopause (5,6)”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Introduction
What the sources say
- Not matchedcites [5] 5. Jick, H., J. Porter, and A. S. Morrison. 1977. Relation between smoking and age of natural menopause. Lancet. i: 1354-1355.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not checked — no full text of the sourcecites [6] 6. Willett, W., M. J. Stampfer, C. Bain, R. Lipnick, F. E. Speizer, B. Rosner, D. W. Cramer, and C. H. Hennekens. 1983. Cigarette smoking, relative weight and menopause. Am. J. Epidemiol. 117:651-658. source
Strength:boosted· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes- Not matched
In the paper
“MacMahon et al. (3) have reported that in nor- mally cycling women who smoke, urinary estrogens in the luteal phase of the cycle are lower than in nonsmokers.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Introduction
What the sources say
- Not checked — no full text of the sourcecites [3] 3. MacMahon, B., D. Trichopoulos, P. Cole, and J. Brown. 1982. Cigarette smoking and urinary estrogens. N. EngI. J. Med. 307:1062- 1065. source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Nicotine con- centrations in the hair of smokers has been reported to be 100 ,uM (27, 28).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
What the sources say
- Not checked — no full text of the sourcecites [27] 27. Sasson, I. M., N. J. Haley, D. Hoffman, E. L. Wynder, D. Hellberg, and S. Nilsson. 1985. Cigarette smoking and neoplasia of the uterine cervix: smoke constituents in cervical mucus. N. Engl. J. Med. 312:315- 316. source
- Not checked — no full text of the sourcecites [28] 28. Ishiyama, I., T. Nagai, and S. Toshida. 1983. Detection of basic drugs from human hair. J. Forensic Sci. 28:380-385. source
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These findings suggest that some nicotinic alkaloids directly inhibit aromatase.”
- Also stated in: § Discussion · hedged
“the experiments examining the effects of nicotine on aromatase in term placental microsomes suggests that nicotine directly inhibits the choriocarcinoma cell aromatase enzyme system.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Also stated in: § Discussion · hedged
In the paper
“Recent epidemiologic evidence suggests that women who smoke have decreased endogenous estrogens (1).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Introduction
What the sources say
- Not checked — no full text of the sourcecites [1] 1. Baron, J. A. 1984. Smoking and estrogen-related disease. Am. J. Epidemiol. 119:9-22. source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, the experiments examining the effects of nicotine on aromatase in term placental microsomes suggests that nicotine directly inhibits the choriocarcinoma cell aromatase enzyme system.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesNone of the sources cited for this claim have been checked yet.
In the paper
“and are at greater risk for postmenopausal osteoporosis (7,8) than nonsmokers.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Introduction
What the sources say
- Not checked — no full text of the sourcecites [7] 7. Daniell, H. W. 1976. Osteoporosis of the slender smoker. Arch. Intern. Med. 136:298-304. source
- Not checked yetcites [8] 8. Williams, A. R., N. S. Weiss, C. L. Ure, J. Ballard, and J. R. Daling. 1982. Effect of weight, smoking and estrogen use on the risk of hip and forearm fractures in postmenopausal women. Obstet. Gynecol. 60:695-699.
Strength:plain· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This finding, in conjunction with the spectral evidence that nicotine interacted directly with placental microsomal cytochrome P-450, suggests that nicotine may inhibit placental aromatase by reversibly altering the function of the active site(s) of the cytochrome P-450 component of the aromatase enzyme system.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Evidence to suggest that nicotine inhibition ofestradiol accumulation was due to a highly specific mechanism includes the following observations:”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“salivary nicotine concentrations of 1 gM (25)”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
What the sources say
- Not checked — no full text of the sourcecites [25] 25. Herning, R I., R. T. Jones, N. L. Benowitz, and A. H. Mines. 1983. How a cigarette is smoked determines blood nicotine levels. Clin. Pharmacol. Ther. 33:84-90. source
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“cervical mucus nicotine concentrations of 10 tsM have been reported (26).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
What the sources say
- Not checked — no full text of the sourcecites [26] 26. Russell, M. A. H., and C. Feyerabend. 1978. Cigarette smoking: a dependence on high-nicotine boli. Drug Metab. Rev. 8:29-57. source
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“In the follicular phase ofthe menstrual cycle, the ovarian follicle that gains dominance produces the majority of circulating es- trogens (29).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
What the sources say
- Not checked — no full text of the sourcecites [29] 29. Haley, N. J., and D. Hoffman. 1985. Analysis for nicotine and cotinine in hair to determine cigarette smoker status. Clin. Chem. 31: 1598-1600. source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“In pregnant women the cotinine concentration in the fetal circulation is 2-4-fold higher than the cotinine concen- tration in the maternal circulation (4).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
What the sources say
- Not checked — no full text of the sourcecites [4] 4. Mochizuki, M., T. Maruo, K. Masuko, and T. Ohtsu. 1984. Effects of smoking on fetoplacental-maternal system during pregnancy. Am. J. Obstet. Gynecol. 149:413-420. source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“In postmenopausal women, circulating androstenedione concentrations less than 2 nM are common (18).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
What the sources say
- Not checked yetcites [18] 18. Estabrook, R. W., J. Peterson, J. Baron, and A. Hildebrant. 1972. A spectrometric measurement of turbid suspensions of cytochromes as- sociated with drug metabolism. In Methods in Pharmacology, Vol. II.
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, the concentrations of nicotine and cotinine that have been re- ported to be present in the body fluids of women who smoke suggests that the in vitro findings reported here may have relevance in vivo.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Rests on an assumption: The concentrations of nicotine and cotinine in body fluids reflect their concentrations at the aromatase enzyme site in ovarian or placental tissues.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The aromatase enzyme system in the granulosa cell is probably exposed to the intrafollicular concentration of androstenedione, 2.5 ,uM.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Therefore, in postmenopausal women, the ratio of nicotine plus cotinine to androstenedione at the peripheral aromatase site may be greater than 1,000 to 1.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
- It may state two separate claims as one. 9
- Probably not a substantial claim. 5
- The quote only partly states this claim. 1
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In all experiments the accumulation ofestradiol always exceeded the accumulation of estrone, and the ratio of estradiol to estrone was in the range of 6:1-10:1.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Addition ofandrostenedione to the choriocarcinoma cultures resulted in the appearance ofboth estradiol and estrone, but not testosterone or dihydrotestosterone.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The addition of nicotine to the choriocarcinoma cell cultures resulted in the inhibition of both estradiol and es- trone accumulation and a corresponding increase in unmetab- olized androstenedione (Table I).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofnicotine, cotinine, and anabasine on estrogen accumulation in choriocarcinoma cell cultures
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Using radioactive progesterone and estradiol, partitioning experiments demonstrated that 95% of these two steroids were present in the culture medium and <5% in the explanted cells.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Load-bearingStrength:boosted· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Ad- dition of 1 MCi of [1,2-3H]progesterone or [6,7-3H]estradiol to 2 X I05 choriocarcinoma cells for 24 h resulted in the conversion of < 15% of the progesterone and <10% of the estradiol to other metabolites as determined by high performance liquid chro- matography.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Characterization ofJar choriocarcinoma cell cultures
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“At the doses used in this study, aqueous extracts of cigarette smoke did not inhibit progesterone accu- mulation or the cell number present in the culture.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Effects ofaqueous extracts ofcigarette smoke on estrogen accumulation in choriocarcinoma cell cultures
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
In the paper
“The addition of aminoglutethimide to preparations ofplacental microsomes elicits a type II cytochrome P450 binding spectrum (20).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
What the sources say
- Not checked — no full text of the sourcecites [20] 20. Meldrum, D. R., B. J. Davidson, I. V. Tataryn, and H. L. Judd. 1981. Changes in steroids with aging in postmenopausal women. Obstet. Gynecol. 57:624-628.
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Kellis and Vickery have reported that naturally occurring plant flavones are potent in- hibitors of aromatase (21).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
What the sources say
- Not checked — no full text of the sourcecites [21] 21. Graves, P. E., and H. A. Salhanick. 1979. Stereoselective inhibition of aromatase by enantiomers of aminoglutethimide. Endocrinology. 105: 52-57. source
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“In placental microsomal preparations, aminoglutethimide competitively inhibits the aromatization of testosterone with an ap- parent Ki of 14 ,uM (20).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > Discussion
What the sources say
- Not checked — no full text of the sourcecites [20] 20. Meldrum, D. R., B. J. Davidson, I. V. Tataryn, and H. L. Judd. 1981. Changes in steroids with aging in postmenopausal women. Obstet. Gynecol. 57:624-628.
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“If the intrafollicular concentration of nicotine plus cotinine were 5 gM, the ratio of nicotine plus cotinine to androstenedione would be 2:1.This ratio is too low to produce significant inhi- bition.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“However, the intrafollicular concentration of androstenedione is -500 times greater, 2.5 ,M (30).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
What the sources say
- Not checked — no full text of the sourcecites [30] 30. Goodman, A. L., and G. D. Hodgen. 1983. The ovarian triad of the primate menstrual cycle. Recent Prog. Horm. Res. 39:1-73. source
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“Jensen et al. have recently reported that in postmenopausal women, smoking may increase the metabolic clearance rate of estradiol (31).”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
What the sources say
- Not checked — no full text of the sourcecites [31] 31. McNatty, K. P., D. M. Smith, A. Makris, R. Osathanondh, and K. J. Ryan. 1979. The microenvironment of the human antral follicle: interrelationships among the steroid levels in antral fluid, the population of granulosa cells, and the status of the oocyte in vivo and in vitro. J. Clin. Endocrinol. Metab. 49:851-860. source
Strength:hedged· not yet calibratedCausal:conditional· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“If the corpus luteum is exposed to a nicotine plus cotinine concentration of 5 gM, then the ratio of nicotine plus cotinine to androstenedione would be 1,000:1.This high ratio could produce significant inhibition of the aro- matase system and a decrease in estrogen production.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes? Based: unclearIt may state two separate claims as one. The quote only partly states this claim.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The aromatase en- zyme system in the cells comprising the corpus luteum is probably exposed to an androstenedione concentration similar to that in the circulation, 5 nM.”
§ Nicotine, Cotinine, and Anabasine Inhibit Aromatase in Human Trophoblast In Vitro > MacMahon et al.
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✗ Based: failsProbably not a substantial claim. The paper may give no reason why it holds.
- Rests on an assumption: In the follicular phase of the menstrual cycle, the circulating androstenedione concentration is approximately 5 nM.
- Rests on an assumption: In the luteal phase of the menstrual cycle, the basement membrane of the dominant follicle is disrupted and the follicular microenvironment is lost.
The authors state this as an assumption.
The aromatase enzyme system in human granulosa cells is similar to placental aromatase.
“If the granulosa cell and placental aromatase are similar, then the in vitro observation that nicotine and cotinine”
The paper relies on this without support.
The concentrations of nicotine and cotinine in body fluids reflect their concentrations at the aromatase enzyme site in ovarian or placental tissues.
“The nicotine and cotinine concentrations present in ovarian follicular fluid and in steroidogenic tissues of women who smoke have not been reported.However, the concentrations of nicotine and cotinine that have been re- ported to be present in the body fluids of women who smoke suggests that the in vitro findings reported here may have relevance in vivo.”
The paper relies on this without support.
In the follicular phase of the menstrual cycle, the circulating androstenedione concentration is approximately 5 nM.
“In the follicular phase of the menstrual cycle, the circulating androstenedione concentration is -5 nM.”
The paper relies on this without support.
In the luteal phase of the menstrual cycle, the basement membrane of the dominant follicle is disrupted and the follicular microenvironment is lost.
“In contrast, in the luteal phase of the menstrual cycle, the basement membrane of the dominant follicle is disrupted, and the follicular microenvironment is lost.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The cited source says what the claim attributes to it.
In the citing paper
“First, nicotine, cotinine, and anabasine inhibit the aromatase enzyme, also called estrogen synthase, in a reversible manner and suppress the production of estrogen [56].”
From The Effect of Tobacco Smoking on Bone Mass: An Overview of Pathophysiologic Mechanisms (2018) · cites this paper as [56]
In the citing paper
“nicotine and cotinine suppress aromatase enzyme activity, contributing to a reduction in estrogen levels [54]”
From An Overlooked Bone Metabolic Disorder: Cigarette Smoking-Induced Osteoporosis (2022) · cites this paper as [54]
Citations
Cites
Bradford, M. M. (1976) · Analytical Biochemistry · doi:10.1016/0003-2697(76)90527-3 · Cited by 255,302
Cigarette smoking, relative weight, and menopause.
WILLETT, W., STAMPFER, M. J., BAIN, C., LIPNICK, R., SPEIZER, F. E., ROSNER, B., CRAMER, D., & HENNEKENS, C. H. (1983) · American Journal of Epidemiology · doi:10.1093/oxfordjournals.aje.a113598 · Cited by 558
McNATTY, K. P., SMITH, D. M., MAKRIS, A., OSATHANONDH, R., & RYAN, K. J. (1979) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jcem-49-6-851 · Cited by 522
Self-citationSmokers of Low-Yield Cigarettes Do Not Consume Less Nicotine
Benowttz, N. L., Hall, S. M., Herning, R. I., Jacob, P., Jones, R. T., & Osman, A.-L. (1983) · New England Journal of Medicine · doi:10.1056/nejm198307213090303 · Cited by 442
Cigarette Smoking and Urinary Estrogens
MacMahon, B., Trichopoulos, D., Cole, P., & Brown, J. (1982) · New England Journal of Medicine · doi:10.1056/nejm198210213071707 · Cited by 404
Jensen, J., Christiansen, C., & Rødbro, P. (1985) · New England Journal of Medicine · doi:10.1056/nejm198510173131602 · Cited by 379
RELATION BETWEEN SMOKING AND AGE OF NATURAL MENOPAUSE
Jick, H., Porter, J., & Morrison, A. (1977) · The Lancet · doi:10.1016/s0140-6736(77)92562-4 · Cited by 345
Inhibition of Human Estrogen Synthetase (Aromatase) by Flavones
Kellis, J. T., & Vickery, L. E. (1984) · Science · doi:10.1126/science.6474163 · Cited by 310
Daniell (1976) · doi:10.1001/archinte.1976.03630030032007 · Cited by 301
SMOKING AND ESTROGEN-RELATED DISEASE
BARON, J. A. (1984) · American Journal of Epidemiology · doi:10.1093/oxfordjournals.aje.a113730 · Cited by 282
Flagged first, then by citations
2 of the 35 references couldn’t be matched to a known paper.
Cited by
Sorted by citations
Pharmacologic Aspects of Cigarette Smoking and Nicotine Addiction
Oates, J. A., Wood, A. J. J., & Benowitz, N. L. (1988) · New England Journal of Medicine · doi:10.1056/nejm198811173192005 · Cited by 969
Michnovicz, J. J., Hershcopf, R. J., Naganuma, H., Bradlow, H. L., & Fishman, J. (1986) · New England Journal of Medicine · doi:10.1056/nejm198611203152101 · Cited by 658
The antiestrogenic effect of cigarette smoking in women
Baron, J. A., Vecchia, C. L., & Levi, F. (1990) · American Journal of Obstetrics and Gynecology · doi:10.1016/0002-9378(90)90420-c · Cited by 594
The dynamic effects of nicotine on the developing brain
Dwyer, J. B., McQuown, S. C., & Leslie, F. M. (2009) · Pharmacology & Therapeutics · doi:10.1016/j.pharmthera.2009.02.003 · Cited by 559
Prenatal exposure to drugs: effects on brain development and implications for policy and education
Thompson, B. L., Levitt, P. R., & Stanwood, G. D. (2009) · Nature reviews. Neuroscience · doi:10.1038/nrn2598 · Cited by 379
Metadata
- Authors
- Barbieri, R. L., Gochberg, J., & Ryan, K. J.
- Affiliations
- Brigham and Women's Hospital (US)
- Venue
- Journal of Clinical Investigation
- Published
- 1986-06-01
- Volume
- 77
- Issue
- 6
- Pages
- 1727-1733
- ISSN
- 0021-9738 (ISSN-L)
- PMC
- PMC370526
- OpenAlex
- W2115000106
- Semantic Scholar
- fe8ede07340192b572ab17ad21fdf2e3ea0e5789
- Cited by
- 197
- References
- 35
- Citations by year
- 2026: 1 · 2025: 3 · 2024: 5 · 2023: 1 · 2022: 8 · 2021: 5 · 2020: 5 · 2019: 3 · 2018: 10 · 2017: 6 · 2016: 4 · 2015: 4 · 2014: 9 · 2013: 5 · 2012: 13
- FWCI
- 3.88
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Journal of Clinical Investigation (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Institutes of Health
- Eunice Kennedy Shriver National Institute of Child Health and Human Development (HD18292)
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Endocrinology › Estrogen and related hormone effects
- Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Smoking Behavior and Cessation
- Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Effects and risks of endocrine disrupting chemicals
- Keywords
- nicotine, cotinine, anabasine, aromatase inhibition, tobacco smoke, estrogen synthesis, choriocarcinoma cells, placental microsomes, androstenedione, testosterone, competitive inhibition, endogenous estrogen
- MeSH terms
- Anabasine, Androstenedione, Carbachol, Cells, Cultured, Choriocarcinoma, Cotinine, Decamethonium Compounds, Dose-Response Relationship, Drug, Estradiol, Female, Hexamethonium Compounds, Humans, Kinetics, Microsomes, Nicotine, Piperidines, Placenta, Pregnancy, Pyrrolidinones, Smoking, Succinylcholine, Trophoblasts, Uterine Neoplasms, Aromatase Inhibitors, In Vitro Techniques
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-11-05, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-11-05 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Statistics and arithmetic are recomputed, not judged.
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