N alpha-Acetyl-gamma-endorphin is an endogenous non-opioid neuropeptide with biological activity.
N alpha-acetyl-gamma-endorphin (Ac gamma E) was identified in the rat neurointermediate pituitary, based on its immunological properties, comigration with synthetic Ac gamma E on HPLC and resistance to aminopeptidase-M degradation. The peptide appeared to be the main form of gamma-endorphin (gamma E) in this tissue and in brain areas remote from the hypothalamus (hippocampus, septum, amygdala). The anterior pituitary, the hypothalamus and the thalamus contained almost exclusively the non-acetylated form of gamma E. In contrast to gamma E, Ac gamma E was completely devoid of specific affinity for brain opiate binding sites. Yet, the peptide mimicked gamma E in that it potently attenuated passive avoidance behaviour in rats, when injected topically into the nucleus accumbens. It is concluded that Ac gamma E is an endogenous neuropeptide with non-opioid biological activity. N alpha-acetylation may not merely represent a mechanism for the inactivation of opioid activities of endorphins, but rather allow the organism to select specific sets of biological activities that reside in the endorphin structure.
Wiegant
V M
VM
Verhoef
J
J
Burbach
J P
JP
van Amerongen
A
A
Gaffori
O
O
Sitsen
J M
JM
de Wied
D
D
D000107:Acetylation; D000626:Aminopeptidases; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D001667:Binding, Competitive; D001923:Brain Chemistry; D018826:CD13 Antigens; D002851:Chromatography, High Pressure Liquid; D004723:Endorphins / Q000032:analysis / Q000494:pharmacology / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D010902:Pituitary Gland / Q000032:analysis*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism
D004723:Endorphins; D011957:Receptors, Opioid; C040967:N-acetyl-gamma-endorphin; D000626:Aminopeptidases; D018826:CD13 Antigens