Prorenin in the cells of the mature human ovarian follicle.

Angiotensin I generating capacity in presence of semi-purified plasma human angiotensinogen, before and after liquid phase trypsin activation, was found in the extracts of the cells retrieved from human hyperstimulated ovarian follicles in women undergoing in-vitro fertilization. More than 90% of this AI generating capacity was due to activated prorenin, whereas only less than 10% was due to active renin. Low levels of angiotensinogen were also present in the extracts (100 ng/ml). This AI forming capacity was completely abolished by pre-incubation with polyclonal anti-renin serum. More than 90% of the cells retrieved from the ovarian follicles were granulosa cells. An intracellular prorenin-renin system can exist in the human ovary than can modulate the ovarian function throughout the menstrual cycle and during pregnancy.