Luteotropic action of estradiol-17 beta and gonadotropic hormones on rat ovarian cells in culture.

Rat granulosa cells isolated from proestrus ovarian follicles and the luteal cells isolated from postovulatory follicles during estrus were cultured as monolayers for 10 days at 37 degrees C in Eagle's medium with 10% calf serum. Progesterone and estrogen concentrations in culture medium were measured by a radioimmunoassay. The activity of delta 5,3 beta-OHSD (delta 5,5 beta hydroxysteroid dehydrogenase) in cultured cells was estimated histochemically. Stimulation of progesterone secretion by cultured luteal cells under the influence of LH (100 ng ml-1), PRL (100 ng ml-1) and estradiol-17 beta (150 ng ml-1) was observed. Granulosa cells, on the other hand, showed no increase in progesterone secretion in the presence of estradiol. LH, PRL (in the same doses as above) and HCG (10 U) enhanced estrogen secretion from luteal cells, but inhibited this process in granulosa cells. The difference might be caused by the presence of theca interna cells in the developing corpus luteum.