DIRECT ACTION OF LH RH AND ITS ANTAGONIST ON ISOLATED BOVINE GRANULOSA-CELLS STEROIDOGENESIS

Progesterone, 4-androstene-3,17-dione, testosterone and estradiol-17 beta secretion by bovine granulosa cells culture without or in the presence of 10, 100 or 10.000 ng/ml LH RH or of its antagonist (D Phe2, D Phe6) LH RH were analyzed. It was observed that both LH RH and its antagonist significantly activated progesterone and estradiol output. LH RH also stimulated, but (D Phe2, D Phe6) LH RH inhibited granulosa 4-androstene-3,17-dione secretion. Both LH RH and its analogue decreased testosterone release by the cell culture. This is the first demonstration of a direct influence of LH RH on bovine ovarian steroidogenesis. The lack of correlation between LH RH and its agonist action on hypophysis and on different gonadal steroids secretion may suggest the differences in the features of receptors to LH RH -related peptides in the various target cells.