Effects of Prostaglandin F2α Treatment on LH and Dibutyryl Cyclic AMP-Stimulated Progesterone Secretion by Isolated Rat Luteal Cells

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Abstract
During prostaglandin F2α (PGF2α)-induced luteolysis in the rat, serum progesterone concentrations fall rapidly. This luteolytic effect of PGF2α may be due to an inhibition of LH-stimulated adenylate cyclase activity. It is not clear, however, whether membrane events alone are responsible for this effect or if additional lesions exist in the steroid biosynthetic pathway. The addition of 1 µM PGF2α to dispersed rat luteal cells significantly inhibited both LH- and dibutyryl cAMP (dbcAMP)-stimulated progesterone secretion. When administered in vivo, PGF2α reduced serum progesterone concentrations within 30 min. Dispersed luteal cells from PGF2α-treated rats produced significantly less progesterone in response to LH and dbcAMP than did cells from untreated rats. These data suggest that PGF2α-induced inhibition of progesterone production occurs at a site beyond cAMP formation in the steroidogenic pathway. Furthermore, the ability of PGF2α to inhibit dbcAMP-stimulated steroidogenesis more effectively in vivo than in vitro suggests that PGF2α may be acting both directly and indirectly to inhibit luteal cell function in vivo.
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