ORG 30276 (APTAA-LHRH) is a potent GnRH antagonist that effectively reduces serum LH and FSH levels in male rats. ORG 30276 significantly decreases unoccupied pituitary GnRH receptors, leading to suppressed gonadotropin secretion. ORG 30276 treatment results in a considerable reduction in mRNA levels of gonadotropin beta-subunits in the pituitary gland. ORG 30276's effects on gonadotropin dynamics can be selectively reversed by the replacement of specific sex steroids, with androgens being particularly effective for the FSH beta-subunit mRNA levels.
