Endocrinology, Vol 129, 1682-1684, Copyright © 1991 by Endocrine Society

ARTICLES

Human galanin: molecular cloning reveals a unique structure

HF Evans and J Shine
Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia.

Galanin, a novel neuropeptide/hypothalamic hormone originally identified and isolated by virtue of its carboxy-terminal amide group, has recently been shown to have a diverse range of biological activities, including potent effects on the secretion of insulin and growth hormone. The physiological role of galanin remains unclear, with different effects being observed when porcine and rat galanin have been used in various animal model systems and in human studies. Molecular cloning of cDNA encoding human galanin and galanin mRNA associated peptide (GMAP) from both pituitary and neuroblastoma sources has revealed a unique and unexpected structure. In contrast to porcine, bovine and rodent galanin, human galanin lacks a carboxy-terminal amide. By analogy to other neurohormones, the absence of carboxy- terminal amidation would be expected to have significant effects on functional properties such as affinity for different receptor subtypes and physiological half life, and may be responsible for the species specificity observed in the action of galanin.