Suppression of the luteinizing hormone releasing effect of luteinizing hormone releasing hormone by arginine-vasotocin.
The concentrations of 17-oxosteroids in the spermatic venous blood of anaesthetized dogs were used as an index of LH release to assess the effects of arginine-vasotocin on the response of the canine pituitary gland to exogenous luteinizing hormone releasing hormone (LH-RH). When injected into the carotid artery, arginine-vasotocin (1.0 microgram/kg body wt) caused no significant alterations in the testicular output of 17-oxosteroids. The administration of LH-RH (5 microgram/kg body wt, a standard dose) into the carotid artery produced typical stimulation of testicular 17-oxosteroid secretion. Administration of arginine-vasotocin (0.01, 0.1 or 1.0 microgram/kg body wt) into the carotid artery 3 h before the administration of a standard dose of LH-RH inhibited the testicular secretion of 17-oxosteroids normally induced by LH-RH. However, pretreatment with arginine-vasotocin (1.0 microgram/kg body wt) did not affect the testicular response to i.v. administration of human chorionic gonadotrophin (5 i.u./kg body wt). These results indicate that in the dog, arginine-vasotocin inhibits the LH-RH-induced release of LH by acting acting directly on the anterior pituitary gland.
D015068:17-Ketosteroids / Q000097:blood / Q000378:metabolism; D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D003864:Depression, Chemical; D004285:Dogs; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D012636:Secretory Rate / Q000187:drug effects; D013737:Testis / Q000187:drug effects / Q000378:metabolism; D014668:Vasotocin / Q000494:pharmacology*
D015068:17-Ketosteroids; D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D014668:Vasotocin