Modification by sex steroids of LHRH response in the polycystic ovary syndrome.

Exogenously administered oestradiol or progesterone was found to induce augmentation of LH and FSH release in response to LHRH administration in patients with the polycystic ovary (PCO) syndrome. The effect of oestradiol upon LH release in the patients was significantly less than the augmented release induced in normal women (P less than 0-02). In contrast, progesterone induced a significantly greater LH release in PCO patients than normal women studied during the early follicular phase (P less than 0-001) but less than that in normal women studied during the mid-follicular phase of the cycle (P less than 0-01). The effects on FSH release in the PCO patients were less marked but similar to those in normal women with comparable basal steroid levels. The results suggest that both oestradiol and progesterone can modify the hypothalamic-pituitary axis in the PCO syndrome in a manner similar to that observed in normal women and a failure of these 'positive feedback' mechanisms does not appear to be the cause of the ovulatory deficiency in this syndrome.