Human granulosa cells with differing steroidogenic potentials were cultured in vitro. The effects of prostaglandin F2α (PGF2α) and PGE2 on the progesterone output and viability of these cells were investigated.
Prostaglandin F2α either alone or in combination with LH and FSH inhibited the production of progesterone over a wide range of concentrations (1–8000 ng/ml). However, the inhibitory effect of PGF2α was 200 times less effective when the cells were exposed to LH and FSH for 6 days before the addition of the prostaglandin. By contrast PGE2, at concentrations from 1 to 500 ng/ml, markedly stimulated the production of progesterone by granulosa cells, and this was not prevented by the addition of PGF2α. The degree of inhibition by PGF2α or stimulation by PGE2 was related to the biosynthetic capacity of the cells.
These studies suggest that PGF2α may act directly on the adenylate cyclase system of human granulosa cells by blocking its activation by LH, and they demonstrate that functional regression of the luteal cell can be induced independently of the blood vascular system.