RELEASE OF VASOPRESSIN BY ENKEPHALIN

Abstract

Leu-enkephalin, its stable analogue [D-Ala²-D-Leu⁵]-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-Ala²-D-Leu⁵]-enkephalin that the antidiuretic response was associated with increased excretion of vasopressin in the urine.