Peritoneal secretion of ovarian hormones and its consequences.

Secretion of ovarian hormones directly into the peritoneal cavity has been repeatedly demonstrated for 25 years, but the consequences of this pathway of secretion have not been fully considered. Circumstantial evidence suggests the following hypotheses: (1) Hormones enter the endometrial cavity through the tubes and influence the endometrial cycle. (2) Androgens are absorbed into the portal venous system and are inactivated in the liver. (3) In polycystic ovary syndrome, ovarian cortical fibrosis inhibits peritoneal secretion of androgens and contributes to hyperandrogenemia. (4) Bypass of the ovarian vein by peritoneal secretion leads to underestimation of ovarian hormone production rates. (5) Peritoneally secreted hormones are absorbed into the broad ligaments of the uterus and returned to the reproductive organs by veno-arterial countercurrent transfer. Some approaches to testing the hypotheses are outlined. If any of the hypotheses are supported by more direct evidence, some aspects of reproductive endocrinology will turn out be even more complicated than they have seemed.