AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 5 581-G587, Copyright © 1986 by American Physiological Society
Potency of natural and synthetic canine gastrin-releasing decapeptide on canine antral muscle
E. A. Mayer, J. R. Reeve Jr, S. Khawaja, P. Chew, J. Elashoff, B. Clark and J. H. Walsh
The carboxyl terminal decapeptide of gastrin-releasing peptide (GRP-10), a
small, naturally occurring bombesin-like peptide, has been isolated from
canine antral muscle, synthesized, and its bioactivity compared with other
synthetic and natural gastrin-releasing peptides on stimulation of
spontaneously occurring contractions of canine circular antral muscle in
vitro. Concentrations of peptides were verified by amino acid analysis and
radioimmunoassay. In this system three forms of natural canine GRP,
synthetic GRP-10, synthetic porcine gastrin-releasing heptacosapeptide
(GRP-27), [Gln3]GRP-10, and [Arg3]GRP-10 all were similar in potency to
synthetic amphibian bombesin. These results differ from the low activity of
GRP-10 previously reported in rat brain. The full biological potency on
canine antral motility and the presence of GRP-10 in nerve fibers in the
gut and in the spinal cord suggest a possible role for this peptide as a
neurotransmitter or neuromodulator in regulation of smooth muscle
contraction.
