Direct inhibitory effect of GnRH on androgen secretion by ovarian interstitial cells

We report here 1) that GnRH and a potent GnRH agonist inhibit basal and LH stimulated ovarian androgen biosynthesis in vitro, 2) that the inhibitory effects of GnRH are dose-dependent and completely inhibited by concomitant treatment with a GnRH antagonist and 3) that the GnRH action is very rapid (t1/2 = 10 min) and persists after thorough washing of the cells. These data suggest that GnRH acts at a stereospecific binding site on ovarian theca and/or interstitial cells (probably the theca cells) to rapidly and perhaps irreversibly inhibit androgen biosynthesis.