Suppression of the luteinizing hormone releasing effect of luteinizing hormone releasing hormone by arginine-vasotocin in immature male dogs.
Arginine-vasotocin (0.1 or 10 ng/kg body wt) was administered into the carotid artery of anaesthetized immature male dogs 3 h before the administration of a standard dose of luteinizing hormone releasing hormone (LH-RH, 5 microgram/kg body wt) into the same vessel. The rate of secretion of 17-oxosteroids by the testes in vivo served as an index of luteinizing hormone (LH) secretion. The administration of LH-RH into the carotid artery of control dogs which had been injected with isotonic saline caused a slight but definite increase in the secretion of testicular 17-oxosteroids. This effect of LH-RH on the testicular secretion of steroids was markedly reduced by pretreatment with arginine-vasotocin. However, the testicular response to the i.v. administration of human chorionic gonadotrophin (5 i.u./kg body wt) was unaffected by pretreatment with arginine-vasotocin (10 ng/kg body wt). These results indicate that in immature male dogs, arginine-vasotocin is able to inhibit the action of LH-RH by acting directly on the anterior pituitary gland.
D015068:17-Ketosteroids / Q000378:metabolism; D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D004285:Dogs; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D012741:Sexual Maturation; D013737:Testis / Q000378:metabolism; D014668:Vasotocin / Q000494:pharmacology*
D015068:17-Ketosteroids; D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D014668:Vasotocin