Increased Serum Prolactin After Administration of Synthetic Thyrotropin Releasing Hormone (Trh) in Man¹

Tea normal volunteers received 100 to 800 ug of TRH intravenously. Serum prolactin was measured by a specific radioimmunoassay before and at intervals after TRH administration. Serum prolactin began to rise within 5 minutes and was maximal after 15 to 20 minutes. The mean peak response at 15 minutes was 11 times the fasting level. Serum prolactin had returned to the baseline by 180 minutes. It is concluded that TRH may be closely related to prolactin releasing factors in crude hypothalamic extracts.