Prostaglandins PGE and PGF in human ovarian follicles: endogenous contents and in vitro formation by theca and granulosa cells.

Abstract

The possible role of prostaglandins of the PGE and PGF series in the follicular compartment of human ovaries or the capacity of that tissue of form them is not well defined. In the present experiment we have examined 1) the endogenous concentrations of PGE and PGF in follicles of human ovaries at various stages of the menstrual cycle, 2) the capacity of separated theca and granulosa to form PGE and PGF in vitro in the presence of substrate arachidonic acid and 3) the possible modulation of that capacity by previous in vitro exposure to hCG (10 IU) alone or in combination with hMG (5 IU). PGE and PGF were determined by radioimmunoassay. Follicles from all stages of the cycle were found to contain measurable amounts of PGE (0.10 - 3.75 ng/follicle) and PGF (0.13 - 1.11 ng/follicle). These compounds were localized more in the theca than the granulosa cells. On a per follicle basis theca showed more capacity to form PGE and PGF in vitro than the corresponding granulosa cells. However, exposure to gonadotrophins stimulated PGE and PGF formation in the granulosa cells and not in the theca. The presence of PGE and PGF in the follicles indicates a physiological role for these compounds in that tissue. Although thecal tissue showed a greater intrinsic capacity to form PGE and PGF, the contribution of granulosa cells may be more important under acute gonadotrophin stimulation.