AJP - Endocrinology and Metabolism, Vol 266, Issue 4 E612-E617, Copyright © 1994 by American Physiological Society
Canine, human, and rat plasma insulin responses to galanin administration: species response differences
T. J. McDonald, E. Tu, S. Brenner, P. Zabel, M. Behme, C. Panchal, I. Hramiak, W. B. Barnett, D. Miller and J. Dupre
Department of Medicine, University of Western Ontario and Vetrogen, London, Canada.
Previous studies demonstrated that porcine galanin is a potent inhibitor of
insulin secretion in many species but fails to alter human insulin
secretion. To resolve whether this discrepancy was due to the use of a
heterologous peptide or to a true species response difference, we studied
the effect of a synthetic replicate of human galanin on glucose-stimulated
insulin secretion in rats, dogs, and humans. On administration into rats,
human and rat galanin significantly inhibited glucose-induced insulin
responses to a similar degree. Similarly, porcine and human galanin
significantly elevated canine plasma glucose and inhibited canine plasma
insulin responses. In contrast, plasma glucose and insulin responses to
glucose administration in humans were unaltered by the addition of human
galanin at or above the maximum effective dose employed in dogs. Possible
effects of galanin administration were seen on human glucagon and
pancreatic polypeptide responses to glucose at the highest dose of human
galanin infused. We conclude that galanin probably does not play a major
role in modulating human beta-cell function.
