Pregnancy interfering action of LHRH and anti-LHRH

Until recently LHRH was believed to be a product of the hypothalamic origin whose primary function was to regulate the secretion of gonadotropin from the pituitary. In the last few years, a large body of experimental evidence has emerged for the existence of the releasing hormone at extrahypothalamic sites. The placenta is one such organ in which the hormone is made and probably has a role in stimulation of the secretion of chorionic gonadotropin as suggested by both in vivo and in vitro experiments. Superagonists of LHRH as well as monoclonal antibodies raised against the decapeptide administered during early pregnancy bring about a sharp decrease in blood chorionic gonadotropin and progesterone levels followed by termination of pregnancy in baboons. The mechanism of the abortifacient action appears to be curtailment of chorionic gonadotropin secretion by the placenta. Whether the immunointerception through LHRH antibodies will hold true for human beings also has to be investigated.