AJP - Gastrointestinal and Liver Physiology, Vol 260, Issue 6 820-G826, Copyright © 1991 by American Physiological Society
Actions of peptide YY and neuropeptide Y on chief cells from guinea pig stomach
J. P. Raufman and L. Singh
Department of Medicine, State University of New York-Health Science Center, Brooklyn 11203-2098.
Peptide YY (PYY), found in intestinal endocrine cells, and neuropeptide Y
(NPY), a structural analogue of PYY found in neurons, inhibit gastric,
pancreatic, and intestinal fluid and electrolyte secretion. We examined the
effects of these peptides on dispersed chief cells from guinea pig stomach.
PYY and NPY, but not pancreatic polypeptide, starting at nanomolar
concentrations, caused a 40-50% inhibition of secretin-, vasoactive
intestinal polypeptide-, prostaglandin E2-, and forskolin-induced increases
in chief cell adenosine 3',5'-cyclic monophosphate (cAMP) content and
pepsinogen secretion. These inhibitory peptides did not alter pepsinogen
secretion caused by cholecystokinin, carbamylcholine, A23187, 8-bromo-cAMP,
or a phorbol ester. The inhibitory effects of PYY on chief cell cAMP
production occurred within 30 s, were independent of phosphodiesterase
activity, and did not affect the actions of cholera toxin. However, the
inhibitory effects of PYY were abolished when chief cells were preincubated
with pertussis toxin, an agent that uncouples inhibitory guanine nucleotide
binding (G) proteins from their receptors. In gastric chief cells, PYY and
NPY attenuate the stimulatory effects of secretagogues whose actions are
mediated by changes in cellular levels of cAMP. PYY-induced attenuation of
chief cell adenylate cyclase activity appears to involve activation of
inhibitory G proteins.
