The hypothalamic-pituitary axis in PCOS

Abstract

The etiology of PCOS is multifactorial and complex, with abnormal ovarian steroidogenesis, hyperinsulinemia, and neuroendocrine abnormalities playing significant interactive roles. In women with PCOS, menstrual cycle dysfunction is accompanied by an increase in GnRH pulse frequency and overall amount, leading to greater LH secretion relative to that of FSH. Evidence suggests that women with PCOS are less sensitive to progesterone-induced slowing of GnRH pulse frequency and that androgens and hyperinsulinemia may mediate this effect. Both genetic and environmental factors impact the presentation and complications associated with PCOS. In particular, obesity attenuates the abnormal LH dynamics through associated factors that act directly at the pituitary.