Insulin administration alters gonadal steroid metabolism independent of changes in gonadotropin secretion in insulin-resistant women with the polycystic ovary syndrome.

The study investigated the effects of insulin on gonadal steroid metabolism in 10 insulin-resistant women with polycystic ovary syndrome (PCO) compared to 5 normal women. It found that insulin increased levels of androstenedione and estradiol while decreasing testosterone and dihydrotestosterone in PCO women, without affecting gonadotropin release. In normal women, insulin only increased estradiol levels. The results suggested that insulin can alter sex hormone levels independently of gonadotropin changes, challenging the notion of a direct link between hyperinsulinemia and hyperandrogenism in PCO.