AJP - Endocrinology and Metabolism, Vol 267, Issue 6 E847-E852, Copyright © 1994 by American Physiological Society
Pancreatic endocrine responses to substance P and calcitonin gene-related peptide in conscious calves
A. V. Edwards and S. R. Bloom
Physiological Laboratory, University of Cambridge, United Kingdom.
Both substance P (SP) and calcitonin gene-related peptide (CGRP; 0.13
micrograms.min-1.kg-1 for 10 min) produced a significant rise in arterial
plasma pancreatic polypeptide (PP) concentration, and additive responses
were obtained when both peptides were infused simultaneously and/or with
acetylcholine (0.7 micrograms.min-1.kg-1 ia). The PP response to SP was
abolished by intravenous infusions of glucose, whereas those to CGRP and
acetylcholine were not significantly affected. Neither SP nor CGRP had any
effect on plasma insulin concentration, either in the presence or absence
of exogenous glucose, whether infused singly or together, or in the
presence of acetylcholine. SP, but not CGRP, produced a small but
statistically significant rise in mean plasma glucagon concentration when
infused together with acetylcholine. These results suggest that SP and CGRP
may modulate the secretion of PP and glucagon in the normal conscious calf
but not that of insulin. It is also possible that SP modulates secretion of
pancreatic glucagon in these animals.
