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Cited by 23Phytoestrogen effects and researchMuscle Physiology and DisordersMuscle metabolism and nutrition

Anabolic Activity of a Soy Extract and Three Major Isoflavones in C2C12 Myotubes

Open access
Zheng, Wenya, Hemker, Marie, Xie, Mingyong, Soukup, Sebastian, Diel, Patrick·2018·Planta Medica
DOI 10.1055/a-0598-4812
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Abstract

Isoflavones have been reported to stimulate muscle growth. The aim of this in vitro study was to examine anabolic activity and associated molecular mechanisms of a soy extract (SoyEx), isoflavone aglycones, and a mixture simulating the composition of SoyEx in C2C12 myotubes. C2C12 cells were differentiated into myotubes. The effects of SoyEx, genistein, daidzein, glycitein, and the mixture of genistein-daidzein-glycitein (Mix) on myotube diameter and number were determined. In addition, the expression of genes and proteins associated with anabolic activity was analyzed. Treatment with SoyEx, genistein, and Mix led to a significant increase of myotube diameter and an increase of the number of myotubes per area compared to the control cell. The increase of diameter by SoyEx was antagonized by an antiestrogen, not by an antiandrogen. Furthermore, gene expressions of insulin growth factor (IGF)-1 and its receptor (IGF-1R), as well as protein expression of myosin heavy chain (MHC), were significantly increased by SoyEx, genistein, and Mix. The effects induced by genistein and Mix were comparable to SoyEx. In conclusion, SoyEx displays an anabolic activity in C2C12 myotubes by binding to ER and modulating IGF-1 and MHC expression. Our studies with isoflavone aglycones and Mix indicate that the isoflavone aglycone with the highest anabolic bioactivity in SoyEx is genistein.

AI snapshot

Written from the paper’s full text.

TL;DR

A soy extract and its isoflavone aglycones, especially genistein, increase C2C12 myotube diameter and anabolic markers through estrogen receptor signaling. The effects are comparable to 17β-estradiol and are associated with increased IGF-1/IGF-1R mRNA and MHC protein expression.

Key findings

  • SoyEx (0.05 µg/mL) increased myotube diameter in a bell-shaped dose-response across 0.0005–50 µg/mL, comparable to E2 at 10 nM; genistein (0.001 µM) and the genistein-daidzein-glycitein mixture (Mix) also significantly increased diameter, whereas daidzein and glycitein alone did not.
  • The antiestrogen ZK191703 antagonized the increased diameter induced by E2 or SoyEx, while the antiandrogen flutamide antagonized DHT-induced hypertrophy but not SoyEx-induced hypertrophy.
  • IGF-1 and IGF-1R mRNA were significantly increased by E2, SoyEx, genistein, or Mix; MuRF1 mRNA was not affected. MHC protein was significantly increased by E2, SoyEx, genistein, daidzein, and Mix, with the highest expression in the E2 group; MyoD protein was not affected.
  • SoyEx contained about 5.3 mg/g genistein, 10.4 mg/g daidzein, and 3.2 mg/g glycitein; among the aglycones, genistein showed the strongest anabolic bioactivity.

Methods

  • C2C12 murine myoblasts were differentiated into myotubes and treated for 48 h with SoyEx (0.0005–50 µg/mL), E2 (1 or 10 nM), DHT (1 µM), ZK191703 (1 µM), flutamide (1 µM), genistein (0.001 µM), daidzein (0.0021 µM), glycitein (0.0006 µM), Mix, or control (0.1% DMSO).
  • Outcomes included myotube diameter (minimum 50 myotubes per group), myotube number in a 0.48 mm² area, real-time PCR for IGF-1, IGF-1R, and MuRF1 normalized to GAPDH, and Western blotting for MHC and MyoD normalized to actin or alpha-tubulin.
  • Statistical analysis used Kruskal-Wallis tests with subsequent Mann-Whitney U-tests; significance was set at p ≤ 0.05, and data were expressed as means ± SD.

Limitations

  • The paper states that the speculation that untreated control myotubes may die by apoptosis or autophagy needs to be investigated in future studies in detail.
  • The paper states that MHC-IIb might be the isoform modulated in this study, but this needs further confirmation.
  • The paper states that statistical hypotheses were not for multiple testing and not for all pairwise comparisons; evident from the text, the study is limited to an in vitro C2C12 myotube model, and individual isoflavones were tested at single concentrations matching 0.05 µg/mL SoyEx, so aglycone dose-response relationships were not established.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1055/a-0598-4812

Cites

38 of 38 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 34 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Treatment with genistein (0.001 μM) and Mix led to significant increases in myotube diameters comparable to the effect induced by SoyEx.

    “Treatment of genistein and Mix led to significant increases of the diameters, which was comparable to the effect induced by SoyEx.”
    Quote in the paperSubstantial claim
  • Findingown data

    IGF-1 mRNA expression in C2C12 myotubes after 48 h treatment was significantly increased by E2, SoyEx, genistein, or Mix.

    “IGF-1 expression (▶ Fig. 5 A) was significantly increased by E2, SoyEx, genistein, or Mix.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: GAPDH is stably expressed across treatments, so normalization to GAPDH yields valid relative mRNA amounts.
  • Findingown data

    Comparing the number of myotubes per area among treatment groups revealed that treatment with all substances (E2, SoyEx, genistein, daidzein, glycitein, Mix) resulted in a significantly higher number of myotubes compared to the control group.

    “Comparing the number of myotubes per area among the treatment groups (▶ Fig. 3 C) revealed treatment with all substances resulted in a significantly higher number of myotubes in the treated groups compared to the control group.”
    Quote in the paperSubstantial claim
  • Findingown data

    The increased myotube diameter induced by treatment with either E2 or SoyEx for 48 h was antagonized by the antiestrogen ZK191703.

    “the increased diameter induced by the treatment of either E2 or SoyEx for 48 h was antagonized by an antiestrogen ZK191703.”
    Quote in the paperSubstantial claim
  • Findingown data

    MuRF1 mRNA expression in C2C12 myotubes was not affected by any of the treatments (E2, SoyEx, genistein, daidzein, glycitein, Mix).

    “However, the expression of MuRF1 (▶ Fig. 5 C) was not affected by any of the treatments.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: GAPDH is stably expressed across treatments, so normalization to GAPDH yields valid relative mRNA amounts.
  • May combine two claims. 25
  • Classified as probably not a substantial claim. 25

  • May combine two claims.

    Findingown data

    The AR antagonist flutamide significantly antagonized DHT-induced myotube hypertrophy but did not decrease myotube diameter when cotreated with SoyEx.

    “a selective antagonist of AR flutamide significantly antagonized the myotube hypertrophy induced by DHT, whereas it was not able to decrease the diameter when cotreated with SoyEx (▶ Fig. 4 B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    E2, SoyEx, genistein, daidzein, and Mix significantly increased MHC protein expression in C2C12 myotubes after 48 h, with the highest expression in the E2 group.

    “E2, SoyEx, genistein, daidzein, and Mix significantly increased MHC protein expression and the highest expression was detected in the E2 group.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Actin and alpha-Tubulin are valid reference proteins for normalization of MHC and MyoD protein expression.

  • May combine two claims.

    Findingown data

    There were no significant differences in IGF-1 expression between E2 and SoyEx, between SoyEx and genistein, or between genistein and Mix.

    “There were no significant differences found between either E2 and SoyEx, between SoyEx and genistein, or between genistein and Mix.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: GAPDH is stably expressed across treatments, so normalization to GAPDH yields valid relative mRNA amounts.

  • May combine two claims.

    Findingown data

    Treatment with SoyEx (0.05 μg/mL) for 48 h increased myotube diameter but did not change the number of myotubes in the same defined area.

    “It is clearly visible that the treatment with SoyEx resulted in an increase of the myotube diameter; however, the number of myotubes in this area did not change after 48 h treatment.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Treatment of C2C12 myotubes with different dilutions of SoyEx (0.0005-50 μg/mL) for 48 h resulted in a bell-shaped dose-response curve, with a significant increase in myotube diameter at 0.05 μg/mL.

    “different dilutions of SoyEx (0.0005-50 µg/mL) resulted in a bell-shaped doseresponse curve, inducing a significant increase in myotube diameter at a concentration of 0.05 µg/mL.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Genistein increased IGF-1 and IGF-1R expressions, and the effects can be comparable to E2, SoyEx, and Mix.

    “Meanwhile, genistein increased IGF-1 and IGF-1R expressions, and the effects can be comparable to E2, SoyEx, and Mix”
    Quote in the paperSubstantial claim
    • Rests on an assumption: GAPDH is stably expressed across treatments, so normalization to GAPDH yields valid relative mRNA amounts.

  • May combine two claims.

    Findingown data

    Both IGF-1 and IGF-1R mRNA expressions were upregulated by SoyEx in C2C12 myotubes.

    “In this study, both IGF-1 and IGF-1R mRNA expressions were detected being upregulated by SoyEx.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: GAPDH is stably expressed across treatments, so normalization to GAPDH yields valid relative mRNA amounts.

  • May combine two claims.

    Findingown data

    MHC protein expression was affected by SoyEx, whereas MyoD was not.

    “Our analysis of the expression of these two proteins in C2C12 myotubes showed that MHC was affected by SoyEx, whereas MyoD was not.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Actin and alpha-Tubulin are valid reference proteins for normalization of MHC and MyoD protein expression.

  • May combine two claims.

    Findingown data

    Daidzein and glycitein also increased MHC protein expressions, but their effects were weaker than those of genistein.

    “Daidzein and glycitein also increased MHC protein expressions; however, the effects were weaker than those of genistein.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Actin and alpha-Tubulin are valid reference proteins for normalization of MHC and MyoD protein expression.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    SoyEx contains other isoflavone derivatives: genistin, 6′′-O-acetyl-genistin, daidzin, 6′′-O-acetyl-daidzin, glycitin, and 6′′-O-acetyl-glycitin.

    “Other isoflavone derivatives (i.e., genistin, 6′′-O-acetyl-gen-istin, daidzin, 6′′-O-acetyl-daidzin, glycitin, 6′′-O-acetyl-glycitin) were also detected (data were shown in our previous paper) [15].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    SoyEx contains about 5.3 mg/g genistein, 10.4 mg/g daidzein, and 3.2 mg/g glycitein.

    “SoyEx contained about 5.3 mg/g genistein, 10.4 mg/g daidzein, and 3.2 mg/g glycitein (data were shown in our previous paper) [15].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [15]

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The MHC expression pattern was similarly regulated as IGF-1 gene expression, further proving the main role of genistein in SoyEx on stimulation of muscle growth.

    “The MHC expression pattern was similarly regulated as IGF-1 gene expression, which further proved the main role of genistein in SoyEx on stimulation of muscle growth.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Genistein has a strong potency of anabolic activity in soy products and among the isoflavone aglycones.

    “indicating a strong potency of anabolic activity of genistein in soy products and among the isoflavone aglycones.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    The IGF-1/PI3K/Akt/PKB/mTOR pathway acts as a positive regulator of muscle growth.

    “The IGF-1/PI3K/Akt/ PKB/mTOR pathway acts as a positive regulator of muscle growth [25].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [25]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    ERβ is involved in the hypertrophy of C2C12 myotubes induced by the phytoecdysteroid ecdysterone.

    “Previously, our group demonstrated that ERβ is involved in the hypertrophy of C2C12 myotubes induced by the phytoecdysteroid ecdysterone [10].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Muscle-specific inactivation of IGF-1R impairs muscle growth due to reduced muscle fiber number and size.

    “muscle-specific inactivation of IGF-1R impairs muscle growth due to reduced muscle fiber number and size [27].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    MyoD and MHC are associated with myostatin expression and localization, which is known as a major negative regulator of muscle growth.

    “they are associated with myostatin expression and localization, which is known as a major negative regulator of muscle growth [31].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31]

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    Isoflavone aglycones from SoyEx induce anabolic effects on C2C12 myotubes by binding to ER and increasing IGF-1 and MHC expression.

    “In summary, isoflavone aglycones from SoyEx induce anabolic effects on C2C12 myotubes by binding to ER and increasing IGF-1 and MHC expression.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The antiestrogen ZK191703 and the antiandrogen flutamide are specific for ER and AR, respectively, in C2C12 myotubes, so the antagonism results indicate ER versus AR involvement.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    In C2C12 neo-formed myotubes, MHC is a major structural protein and acts as a differentiation marker.

    “In C2C12 neo-formed myotubes, MHC is a major structural protein and acts as a differentiation marker [13].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [13]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    MyoD and MHC play important roles during the process of myogenesis in C2C12 cells.

    “MyoD and MHC play important roles during the process of myogenesis in C2C12 cells [30]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [30]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Differentiated myotubes of C2C12 cells exhibit a hypertrophic response to growth factors like IGF-1 and E2, characterized by changes of diameters in myotubes and an activation of protein synthesis.

    “Differentiated myotubes of C2C12 cells exhibit a hypertrophic response to growth factors like IGF-1 and E2, characterized by changes of diameters in myotubes and an activation of protein synthesis [9].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    C2C12 cells have been used extensively as an in vitro model to study both muscle differentiation and hypertrophy.

    “C2C12 cells, a myoblast cell line derived from murine satellite cells, have been used extensively as an in vitro model to study both muscle differentiation and hypertrophy [9].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    IGF-1 directly interacts with its own receptor, IGF-1R, followed by activating the PI3K/Akt pathway.

    “IGF-1 directly interacts with its own receptor, IGF-1R, followed by activating the PI3K/Akt pathway [14].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14]

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    The hypertrophic effect of SoyEx can be antagonized by an antiestrogen but not by an antiandrogen, indicating that the anabolic effect of SoyEx is mediated via interaction with the ER signaling pathway rather than the AR pathway.

    “In ▶ Fig. 4, it is shown that the hypertrophic effect of SoyEx can be antagonized by the antiestrogen but not by the antiandrogen, indicating the anabolic effect of SoyEx is mediated via an interaction with the ER signaling pathway rather than the AR pathway.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The antiestrogen ZK191703 and the antiandrogen flutamide are specific for ER and AR, respectively, in C2C12 myotubes, so the antagonism results indicate ER versus AR involvement.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    IGF-1 has been reported to stimulate muscle growth by decreasing MuRF1.

    “IGF-1 has been reported to stimulate muscle growth by decreasing MuRF1 [28].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [28]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Genistein is able to affect muscle growth through ERβ signaling pathway, showing an increased expression of MHC.

    “Another in vivo study in our group showed that genistein is able to affect muscle growth through ERβ signaling pathway, showing an increased expression of MHC [11].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    An in vivo study showed that MHC composition was shifted from fast to slow MHC isoform in soleus and extensor digitorum longus by ovariectomy in rats.

    “An in vivo study showed that MHC composition was shifted from fast to slow MHC isoform in soleus and extensor digitorum longus by ovariectomy in rats [12].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [12]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    The substances were compared only to the control group or between two groups as indicated; the hypotheses of statistical analysis were not for multiple testing and did not exist for all pairwise comparisons.

    “The substances were compared only to control group or between two groups as indicated in ▶ Fig. 4. The hypotheses of statistical analysis were not for multiple testing and existed not for all pairwise comparisons.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The identity of each compound was confirmed by retention time and UV-Vis spectra.

    “The identity of each compound was confirmed by the retention time and the UV-Vis spectra.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In rat L6 skeletal muscle cells, genistein promoted cell proliferation at doses ≤ 1 μM, which is in agreement with our data demonstrating a stimulation of protein synthesis in C2C12 myotubes at the same dose.

    “In rat L6 skeletal muscle cells, genistein promoted cells proliferation at doses ≤ 1 µM, which is in agreement with our datademonstrating a stimulation of protein synthesis in C2C12 myotubes at the same dose [16].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [16]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Isoflavones are discussed as an alternative for HRT because of their similar chemical structure to E2.

    “Isoflavones are naturally occurring diphenolic compounds (▶ Fig. 1 A) and are discussed as an alternative for HRT because of their similar chemical structure to E2.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    HRT has a complex pattern of risks and benefits.

    “However, HRT has a complex pattern of risks and benefits [3,4].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [3]

      Not checked in the free run.

    • cites [4]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Minimal 50 myotubes per group of all forms were measured.

    “Minimal 50 myotubes per group of all forms were measured by using the Axiovision LE software.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    For each group, more than seven pictures were taken.

    “For each group, more than seven pictures were taken.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Relative mRNA amounts of target genes were calculated after normalization to a housekeeping gene (GAPDH).

    “Relative mRNA amounts of target genes were calculated after normalization to a housekeeping gene (GAPDH).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Study design and conductnone given

    In all groups, the same number of cells was seeded and a comparable number of myotubes was differentiated.

    “In all groups, the same number of cells was seeded and a comparable number of myotubes was differentiated”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    C2C12 cells express both AR and ER.

    “It is well known that C2C12 cells ex- press both AR and ER [19,20].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [19]

      Not checked in the free run.

    • cites [20]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The quality of RNA was checked by agarose gel electrophoresis and RNA was quantified by spectrophotometry.

    “The quality of RNA was checked by agarose gel electrophoresis and the RNA was quantified by spectrophotometry (NanoDrop 1000, Thermo Scientific).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Aglycones are absorbed faster and in higher amounts than their glycosides after dietary isoflavone intake in humans.

    “It was found that the aglycones are absorbed faster and in higher amounts than their glycosides after dietary isoflavone intake in humans [24]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [24]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Genistein inhibited cell growth by suppressing AR transcription in prostate cancer cell lines.

    “Some studies pointed out that genistein inhibited cell growth by suppressing AR transcription in prostate cancer cell lines [21].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Protein expression of MHC and MyoD was respectively related to the reference protein actin, alpha-Tubulin.

    “Protein expression of MHC and MyoD was respectively related to the reference protein actin, alpha-Tubulin.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    To avoid irregular myotube growth affecting the results, pictures were taken of marked spots before chemical treatment, which could be compared to pictures of the same spot after treatment.

    “In order to avoid that irregular myotube growth would affect the results, pictures were taken of marked spots before chemical treatment, which could be compared to the pictures of the same spot after the treatment.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Soy is the main source for isoflavones.

    “Soy (Glycine max [L.] Merr., Leguminosae) is the main source for isoflavones [5].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5]

      Not checked in the free run.

43 of 43

  • The paper relies on this without support.

    The antiestrogen ZK191703 and the antiandrogen flutamide are specific for ER and AR, respectively, in C2C12 myotubes, so the antagonism results indicate ER versus AR involvement.

    “the increased diameter induced by the treatment of either E2 or SoyEx for 48 h was antagonized by an antiestrogen ZK191703.”
    “a selective antagonist of AR flutamide significantly antagonized the myotube hypertrophy induced by DHT, whereas it was not able to decrease the diameter when cotreated with SoyEx”

  • The paper relies on this without support.

    GAPDH is stably expressed across treatments, so normalization to GAPDH yields valid relative mRNA amounts.

    “Relative mRNA amounts of target genes were calculated after normalization to a housekeeping gene (GAPDH).”

  • The paper relies on this without support.

    Actin and alpha-Tubulin are valid reference proteins for normalization of MHC and MyoD protein expression.

    “Protein expression of MHC and MyoD was respectively related to the reference protein actin, alpha-Tubulin.”
3 of 3

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?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Figure 4 reverses the AR and ER panel labels

    Minor

    The results describe Fig. 4 A as the antiestrogen experiment and Fig. 4 B as the antiandrogen experiment, but the caption assigns A to AR and B to ER.

  • Methods' Mix concentration range excludes one stated component

    Minor

    The methods give a Mix concentration range of 0.001-0.0021 μM, whereas the figure caption includes a 0.0006 μM component in Mix, below that range.

2 of 2

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Authors
Zheng, W., Hemker, M., Xie, M., Soukup, S., & Diel, P.
Affiliations
  • German Sport University Cologne (DE)
  • Nanchang University (CN)
  • Max Rubner Institut (DE)
ORCID
Venue
Planta Medica
Publisher
Georg Thieme Verlag KG
Published
2018-04-12
Volume
84
Issue
14
Pages
1022-1029
ISSN
  • 0032-0943 (ISSN-L)
  • 1439-0221
DOI
10.1055/a-0598-4812
OpenAlex
W2796748628
Semantic Scholar
cc8fa82c252658cb39a496d4b30a20d2aa8a917b
Cited by
23
References
37
Citations by year
2026: 3 · 2025: 2 · 2024: 2 · 2023: 4 · 2022: 5 · 2021: 3 · 2020: 1 · 2019: 3
FWCI
1.34
Type
journal article
Language
en
Open access
Locations
  • Planta Medica (publishedVersion)
  • PubMed (publishedVersion)
  • OpenAgrar (submittedVersion)
Funders
  • Deutsche Forschungsgemeinschaft
  • China Scholarship Council
Topics
  • Health Sciences › Medicine › Pathology and Forensic Medicine › Phytoestrogen effects and research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Muscle Physiology and Disorders
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
Keywords
soybean extract, isoflavone aglycones, genistein, daidzein, glycitein, C2C12 myotubes, estrogen receptor, insulin-like growth factor I, IGF-1 receptor, myosin heavy chain, muscle hypertrophy
MeSH terms
Animals, Cell Line, Drug Therapy, Combination, Insulin-Like Growth Factor I, Isoflavones, Plant Extracts, Glycine max, Receptor, IGF Type 1, Muscle Fibers, Skeletal, Myosin Heavy Chains, Genistein, Myoblasts, Anabolic Agents, Mice, 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.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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