Cessation of progesterone secretion by LH-RH in hypophysectomized pregnant and hypophysectomized, prolactin injected pseudopregnant rats

LH-RH causes pregnancy failure in hypophysectomized rats. This study investigated whether this failure was due to an action of LH-RH upon the fetus, placenta, uterus, or ovary. Pseudopregnant, hypophysectomized, prolactin treated rats were subjected to uterine trauma to develop the decidual cell response or were hysterectomized. Deciduoma formation and serum progesterone valves were significantly decreased in all LH-RH treated animals. These observations suggest that LH-RH inhibits prolactin maintained progesterone secretion in hypophysectomized rats by a direct action of the hormone on the ovary.