CoChat
Sign Up
Cited by 157Thyroid Disorders and TreatmentsThyroid Cancer Diagnosis and TreatmentThyroid and Parathyroid Surgery

Triiodothyronine and Thyroxine in Hyperthyroidism COMPARISON OF THE ACUTE CHANGES DURING THERAPY WITH ANTITHYROID AGENTS

Open access
Abuid, J., Larsen, P. R.·1974·Journal of Clinical Investigation
DOI 10.1172/jci107744PMC PMC301541
Open this paper in CoChat — free accountOpen PDF

Abstract

In 66 untreated patients with hyperthyroidism, serum triiodothyronine (T(3)) and thyroxine (T(4)) concentrations were measured by immunoassay. The mean T(3) level was 478+/-28 ng/100 ml (all values mean+/-SEM) and the T(4) was 20.6+/-0.6 mug/100 ml. The serum T(4)/T(3) ratio by weight was 48+/-2 as opposed to a value of 71+/-3 in euthyroid adults. There was a significant inverse correlation of the T(4)/T(3) ratios with serum T(3) (r=0.77; P<0.01) but not with serum T(4)(r=0.21). These results suggested that relative overproduction of T(3) is consistently present in patients with hyperthyroidism. To examine the acute effects of various antithyroid agents on serum T(3) and T(4) concentrations, iodide, propylthiouracil (PTU), and methylmercaptoimidazole (MMI) were given alone to mine patients, and serial T(3) and T(4) measurements were made. There was an acute decrease in serum T(3) over the first 5 days in the three iodide and three PTU-treated patients which was greater than that seen in the MMI group. This suggested that PTU and MMI had different effects on T(3) production. To compare the effects of PTU and MMI under conditions in which thyroidal hormone release was minimized, these drugs were given in combination with iodide. The mean daily dosage of PTU was 827 (n=11) and of MMI was 88 (n=8). In the PTU+iodide group, the initial serum T(3) concentration was 586+/-61 ng/100 ml and decreased significantly to 326+/-41 on day 1 and to 248+/-21 on days 2 and 3, respectively, and did not change further on days 4 and 5. In the MMI + iodide group, basal serum T(3) was 645+/-90 ng/100 ml and decreased to 568+/-81, 452+/-73, and 344+/-51 on days 1, 2, and 3, respectively, and did not change thereafter. While the initial T(3) concentrations in serum were not different in the PTU and MMI groups, the T(3) concentrations in the PTU patients were significantly lower on days 1 and 2 and during the apparent plateau period on days 3-5. Serum T(4) concentrations decreased gradually in both groups, from 23.9+/-2.0 mug/100 ml, initially, to 17.5+/-1.6 on day 5 in the PTU group and from 22.0+/-2.6 to 14.6+/-2.0 in the MMI-treated patients. The T(4) values were not significantly different at any time. These changes resulted in increases in the serum T(4)/T(3) ratios in both groups, but these ratios were substantially higher in the patients treated with PTU + iodide. The initial serum T(4)/T(3) ratio was 43+/-3 and increased to 74+/-7 and 88+/-7 on days 1 and 2 in the PTU group, reaching a plateau value of 91+/-7 during days 3-5. Comparable values for MMI-treated patients were 35+/-2, 42+/-3, 52+/-6, and 54+/-3 during the plateau period. Previous investigations have shown that PTU inhibits T(4) deiodination in hyperthyroid patients and decreases T(3) production from T(4) in animals. The greater acute decrease in serum T(3) and the higher serum T(4)/T(3) ratios in the PTU-treated patients seems best explained by an inhibition of peripheral T(3) production by this agent. This conclusion is further supported by a direct relationship between the T(4)/T(3) ratio on days 3-5 and the dose of PTU administered. These results further suggest that both thyroidal and extrathyroidal pathways contribute substantially to the apparent overproduction of T(3) in hyperthyroidism.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1172/jci107744

Cites

17 of 17 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

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?

  • Therapeutic measures specifically intended to decrease T4-to-T3 conversion include preferential use of PTU over MMI, glucocorticoid therapy, and beta-adrenergic blocking agents such as propranolol with selective ability to inhibit type 1 deiodinase.

    “A number of therapeutic measures are specifically intended to decrease T 4 -to-T 3 conversion, such as the preferential use of PTU over MMI (229,230), glucocorticoid therapy (231), and the use of b-adrenergic blocking agents such as propranolol, with selective ability to inhibit type 1 deiodinase (232).”

    From 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis (2016) · cites this paper as [229]

  • In an early article comparing acute changes in thyroid hormone level after initiation of PTU or MMI, T3 levels dropped by approximately 45% in the first 24 hours of PTU therapy compared to an approximately 10%-15% decrease after starting MMI.

    “For example, an early article comparing acute changes in thyroid hormone level after initiation of PTU or MMI found that T 3 levels dropped by approximately 45% in the first 24 hours of PTU therapy compared to an approximately 10%-15% decrease after starting MMI (229).”

    From 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis (2016) · cites this paper as [229]

Self-check

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

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Ingbar, S. H., and K. A. Woeber. 1968. The thyroid gland. In Textbook of Endocrinology. R. H. Williams, editor. W. B. Saunders Company, Philadelphia. 4th edition. 214.

Cited by

Sorted by citations

Related

Authors
Abuid, J., & Larsen, P. R.
Affiliations
University of Pittsburgh (US)
Venue
Journal of Clinical Investigation
Publisher
American Society for Clinical Investigation
Published
1974-07-01
Volume
54
Issue
1
Pages
201-208
ISSN
0021-9738 (ISSN-L)
DOI
10.1172/jci107744
PMC
PMC301541
OpenAlex
W2081779848
Cited by
156
References
17
Citations by year
2026: 2 · 2025: 2 · 2024: 4 · 2023: 4 · 2022: 3 · 2021: 8 · 2020: 5 · 2019: 6 · 2018: 3 · 2017: 9 · 2016: 4 · 2015: 2 · 2014: 1 · 2012: 1
FWCI
6.77
Type
journal article
Language
en
Open access
Locations
  • Journal of Clinical Investigation (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
National Institutes of Health
Topics
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Disorders and Treatments
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Cancer Diagnosis and Treatment
  • Health Sciences › Medicine › Surgery › Thyroid and Parathyroid Surgery
Keywords
hyperthyroidism, triiodothyronine, thyroxine, T3/T4 ratio, antithyroid drugs, propylthiouracil, methimazole, iodide, thyroid hormone synthesis, thyroid hormone secretion
MeSH terms
Dose-Response Relationship, Drug, Humans, Hyperthyroidism, Iodine, Methimazole, Propylthiouracil, Antithyroid Agents, Thyroid Gland, Thyroxine, Triiodothyronine

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.

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 ›

Are you an author, or do you see a problem with this page? Request a review