RELEASE OF VASOPRESSIN BY ENKEPHALIN

Abstract

Leu‐enkephalin, its stable analogue [D‐Ala 2 ‐D‐Leu 5 ]‐enkephalin and the C‐fragment of lipotropin (β endorphin) injected intravenously in the rat produced anti‐diuretic responses which were inhibited reversibly by naloxone. It was shown for Leu‐enkephalin that injection into the cerebral ventricles was at least ten times more effective than intravenous injection and for [D‐Ala 2 ‐D‐Leu 5 ]‐enkephalin that the antidiuretic response was associated with increased excretion of vasopressin in the urine.