{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T23:23:54Z","timestamp":1792106634582,"version":"4.4.0"},"reference-count":12,"publisher":"The Endocrine Society","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2006,1,1]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Context: Drug-drug interactions are common but often are discovered only long after initial drug release. Metformin has been available in the United States for 9 yr and elsewhere for many years, but as of yet there are no reports that the drug modifies thyroid hormone economy.<\/jats:p><jats:p>Objective: The objective of the study was to describe the clinical and biochemical findings of four patients with chronic hypothyroidism, previously euthyroid on fixed doses of l-T4 for several years, in whom the metformin was initiated.<\/jats:p><jats:p>Design: This was a retrospective review.<\/jats:p><jats:p>Setting: The study was conducted at a tertiary care military hospital providing care to active-duty soldiers, sailors, and marines, retirees of the armed forces, and their eligible dependents.<\/jats:p><jats:p>Participants: Four patients with chronic hypothyroidism who were placed on metformin participated in the study.<\/jats:p><jats:p>Intervention, Main Outcome Measure: Serum TSH, free T4, and free T3 levels were measured during metformin treatment.<\/jats:p><jats:p>Results: Initiation of treatment with metformin (three for diabetes mellitus and one for nonalcoholic steatohepatitis) caused suppression of TSH to subnormal levels without clinical symptoms of hyperthyroidism in any patients. There was no change in free T4 or free T3 in patient 1.<\/jats:p><jats:p>Conclusions: No other potential causes of TSH suppression, including medication changes or interference in the TSH assay, could be identified. The mechanism of the fall in serum TSH in these four patients is unclear at this time. Should these findings be confirmed in larger prospective studies, metformin\u2019s ability to suppress TSH without causing clinical or chemical hyperthyroidism might render this drug a useful adjunct to the treatment of patients with thyroid cancer.<\/jats:p>","DOI":"10.1210\/jc.2005-1210","type":"journal-article","created":{"date-parts":[[2006,1,9]],"date-time":"2006-01-09T22:27:51Z","timestamp":1136845671000},"page":"225-227","source":"Crossref","is-referenced-by-count":134,"title":["Thyrotropin Suppression by Metformin"],"prefix":"10.1210","volume":"91","author":[{"given":"Robert A.","family":"Vigersky","sequence":"first","affiliation":[{"name":"Endocrinology Service, Walter Reed Army Medical Center, Washington, DC 20307"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amy","family":"Filmore-Nassar","sequence":"additional","affiliation":[{"name":"Endocrinology Service, Walter Reed Army Medical Center, Washington, DC 20307"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Allan R.","family":"Glass","sequence":"additional","affiliation":[{"name":"Endocrinology Service, Walter Reed Army Medical Center, Washington, DC 20307"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"80","reference":[{"key":"2020071617263910600_R1","doi-asserted-by":"crossref","first-page":"1364","DOI":"10.2337\/diacare.21.8.1364","article-title":"Lactic acidosis with therapeutic metformin blood level in a low-risk diabetic patient.","volume":"21","author":"Al-Jebawi","year":"1998","journal-title":"Diabetes Care"},{"key":"2020071617263910600_R2","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1007\/BF03350893","article-title":"Three-month treatment with metformin or dexfenfluramine does not modify the effects of diet on anthropometric and endocrine-metabolic parameters in abdominal obesity.","volume":"22","author":"Oleandri","year":"1999","journal-title":"J Endocrinol Invest"},{"key":"2020071617263910600_R3","doi-asserted-by":"crossref","first-page":"607","DOI":"10.1042\/bj3480607","article-title":"Evidence that metformin exerts it anti-diabetic effects through inhibition of the complex 1 of the mitochondrial respiratory chain.","volume":"348","author":"Owen","year":"2000","journal-title":"Biochem J"},{"key":"2020071617263910600_R4","doi-asserted-by":"crossref","first-page":"1167","DOI":"10.1172\/JCI13505","article-title":"Role of AMP-activated protein kinase in mechanism of metformin action.","volume":"108","author":"Zhou","year":"2001","journal-title":"J Clin Invest"},{"key":"2020071617263910600_R5","doi-asserted-by":"crossref","first-page":"757","DOI":"10.2337\/diab.27.7.757","article-title":"Enhancement of the mitochondrial Ca2+ uptake rate by phenethylbiguanide and other organic cations with hypoglycemic activity.","volume":"27","author":"Davidoff","year":"1978","journal-title":"Diabetes"},{"key":"2020071617263910600_R6","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1101\/gad.14.2.121","article-title":"The coregulator exchange in transcriptional functions of nuclear receptors.","volume":"14","author":"Glass","year":"2000","journal-title":"Genes Dev"},{"key":"2020071617263910600_R7","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1046\/j.1365-2796.2003.01213.x","article-title":"Effects of short-term treatment with metformin on serum concentrations of homocysteine, folate and vitamin B12 in type 2 diabetes mellitus: a randomized, placebo-controlled trial.","volume":"254","author":"Wulffele","year":"2003","journal-title":"J Intern Med"},{"key":"2020071617263910600_R8","first-page":"693","author":"Stocker","year":"2005"},{"key":"2020071617263910600_R9","doi-asserted-by":"crossref","first-page":"705","DOI":"10.1210\/jcem-61-4-705","article-title":"Bioavailability of albumin bound testosterone.","volume":"61","author":"Manni","year":"1985","journal-title":"J Clin Endocrinol Metab"},{"key":"2020071617263910600_R10","doi-asserted-by":"crossref","first-page":"3666","DOI":"10.1210\/jcem.84.10.6079","article-title":"A critical evaluation of simple methods for the estimation of free testosterone in serum.","volume":"84","author":"Vermeulen","year":"1999","journal-title":"J Clin Endocrinol Metab"},{"issue":"Suppl 1","key":"2020071617263910600_R11","first-page":"21","article-title":"The movement of thyroid hormones in the central nervous system","volume":"19","author":"Robbins","year":"1992","journal-title":"Acta Med Austriaca"},{"key":"2020071617263910600_R12","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1016\/S0305-0491(96)00212-X","article-title":"The evolution of gene expression, structure and function of transthyretin.","volume":"116","author":"Schreiber","year":"1997","journal-title":"Comp Biochem Physiol B"}],"container-title":["The Journal of Clinical Endocrinology &amp; 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