Endocrine Abstracts

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder, affecting 10–18% of women of reproductive age. Based on the Rotterdam consensus, PCOS is diagnosed by at least two of the following three criteria: oligo- or anovulation, hyperandrogenism, and polycystic ovaries on ultrasound. PCOS is also a metabolic disorder since many affected women present with obesity, insulin resistance and associated metabolic comorbidities. Despite its prevalence, the pathophysiology of PCOS is still not understood. Increased androgens levels are considered a key driver in the etiology of PCOS, supported by the development of PCOS-like reproductive and metabolic derangements in various animal models. Women with PCOS also present with 2- to 3-fold increased levels of anti-Müllerian hormone (AMH). AMH is secreted by the granulosa cells of small growing follicles. Since AMH levels correlate strongly with the number of growing follicles, AMH levels are suggested as a marker for PCOS to be used as a proxy for the PCO morphology. Additionally, AMH has been implicated in the pathophysiology of PCOS. AMH suppresses FSH sensitivity of growing follicles, in part by decreasing FSH-induced aromatase expression. It is has therefore been suggested that the increased AMH levels contribute to the anovulatory and hyperandrogenic phenotype of PCOS. However, treatment of mice with AMH did result in a PCOS-like phenotype. Intriguingly, prenatal exposure to excess AMH did induce a PCOS-like phenotype in female offspring. This recent study showed that AMH treatment resulted in an altered intra-uterine environment since AMH exposure decreased placental aromatase expression. As a result, the female offspring were exposed to the elevated maternal testosterone levels during gestation, which in turn induces the PCOS-like phenotype. These studies shed new light on the role of AMH in the pathophysiology of PCOS and warrants further studies on the mechanism of action of AMH.