title: The effect of metformin on the hypothalamic-pituitary-thyroid axis in women with polycystic ovary syndrome and subclinical hypothyroidism.
abstract: The effect of metformin treatment on the hypothalamic-pituitary-thyroid axis is relatively weakly understood. This study included 24 prediabetic patients with polycystic ovary syndrome and untreated subclinical hypothyroidism, 12 of whom had already been treated with bromocriptine (5.0-7.5 mg daily). The included patients received metformin (2.55 g daily) for 6 months. Glucose homeostasis markers, serum prolactin, and thyroid function tests were determined before, after 3 months, and at the end of the treatment. Beyond improving glucose homeostasis, metformin administered for 6 months reduced serum levels of thyrotropin but did not affect serum levels of total and free thyroid hormones. Thyrotropin-lowering effect of this agent was stronger in patients not treated with bromocriptine than in patients receiving this drug, and weakly correlated with an improvement in insulin sensitivity. The obtained results indicate that metformin treatment may have an impact on thyrotrope function in hypothyroid patients, probably by enhancing the effect of thyroid hormone action in the pituitary.
authors: Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Medyków 18, PL 40-752, Katowice, Poland.
authors: Robert
authors: R
authors: Krysiak
authors: Bogusław
authors: B
authors: Okopien
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System; D007037:Hypothyroidism / Q000097:blood*; D008687:Metformin / Q000494:pharmacology*; D008875:Middle Aged; D011085:Polycystic Ovary Syndrome / Q000097:blood*; D013961:Thyroid Gland; D013972:Thyrotropin / Q000097:blood
chemical_list: D013972:Thyrotropin; D008687:Metformin
keywords: hypothyroidism; metformin; polycystic ovary syndrome; prediabetes; thyroid hormones; thyrotropin