[Polycystic ovary syndrome (author's transl)].

Recent developments have occurred in the understanding of the physiopathology of polycystic ovary (Stein-Leventhal) syndrome. The authors describe in particular the present bio-chemical definition of so-called type I polycystic ovary syndrome: very high and anarchical secretion of LH by the pituitary, explosive response of LH during the LH-RH test, contrasting with normal levels of FSH under basal conditions and after stimulation with LH-RH. In the polycystic ovary, positive and negative feedback exerted by oestrogens at the level of the hypothalamus are intact. In particular, the administration of clomiphene results, in the majority of cases, in ovulation in patients with this disorder. The mechanisms (ovarian hyperproduction of androstenedione, increased transformation of androstenedione into testosterone then dihydrotestosterone and into androstanediol) responsible for the development of hyperandrogenism during polycystic ovary syndrome are also analysed.