Impaired Gonadotropin-Lowering Effects of Metformin in Postmenopausal Women with Autoimmune Thyroiditis: A Pilot Study

Metformin has been found to reduce elevated gonadotropin levels. Hashimoto’s thyroiditis is the most common thyroid disorder in iodine-sufficient areas, and it often develops postmenopausal women. The aim of this study was investigate whether autoimmune determines impact metformin on gonadotrope secretory function. Two matched groups women were studied: 35 with euthyroid (group A) without disorders B). Throughout study, all participants received oral (2.55–3 g daily). Plasma glucose, insulin, gonadotropins, estradiol, progesterone, thyrotropin, free hormones, prolactin, adrenocorticotropic hormone, insulin-like growth factor-1, hsCRP, peroxidase, thyroglobulin antibody titers measured at beginning six months later. At entry, both differed peroxidase titers, hsCRP In group A, baseline correlated positively negatively insulin sensitivity. Although improved glucose homeostasis reduced levels groups, these effects more pronounced B than A. Only did decrease FSH tend LH Thyroid remaining hormones not change throughout study. their values degree improvement sensitivity, as well treatment-induced reduction hsCRP. Moreover, gonadotropins sensitivity A depended titers. obtained results indicate that coexisting impairs gonadotropin-lowering