an in-vitro superfusion system was used to study the effects of the endogenous opioid peptides [ met ] -enkephalin ( and its long-lasting analogue [ d-ala2 , met ] -enkephalinamide ) , [ leu ] -enkephalin and beta-endorphin and of the opiate antagonist naloxone , on the secretion of lhrh from the mediobasal hypothalamus of the cockerel .
C0023610
lhrh
C0020663
hypothalamus