Influence of human chorionic gonadotropin in vivo on steroid formation and gonadotropin responsiveness of isolated human preovulatory follicular cells

Abstract

Granulosa and thecal cells of preovulatory follicles taken from 12 women were isolated and incubated separately for 2 hours in the presence and absence of human chorionic gonadotropin (hCG). To six of these women, an ovulatory dose of hCG (9000 IU) had been given 24 to 30 hours before excision of the follicle. Following incubation, cellular cyclic adenosine 3':5' monophosphate (cAMP) levels and the medium content of progesterone (P), androstenedione (A), and 17 beta-estradiol (E2) were determined. All follicles appeared healthy and well developed, and the oocytes recovered were morphologically normal and mature. Exposure to hCG in vivo caused a shift in steroidogenesis from A toward P formation in isolated thecal cells and a marked increase in the P production by the granulosa cells of the preovulatory follicles. Furthermore, the thecal cells, but not the granulosa cells, developed refractoriness to further stimulation with hCG in vitro.