AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 6 1359-R1364, Copyright © 1995 by American Physiological Society
Characterization of the endogenous intestinal peptide that stimulates the rectal gland of Scyliorhinus canicula
W. G. Anderson, J. M. Conlon and N. Hazon
Department of Biology and Preclinical Medicine, Gatty Marine Laboratory, University of St. Andrews, Fife, United Kingdom.
It has been postulated that gut peptides play a major role in the
regulation of rectal gland secretion in elasmobranchs. An isolated perfused
rectal gland secretion in elasmobranchs. An isolated perfused rectal gland
preparation was developed for Scyliorhinus canicula that responded to
dibutyryl 3',5'-cyclic monophosphate plus 3-isobutyl-1-methylxanthine,
increasing chloride clearance rates threefold over basal levels. Activity
was stimulated by an endogenous peptide, isolated in pur form by
reverse-phase high-performance liquid chromatography from the intestine of
S. canicula. The primary structure was established as
Ser-Pro-Ser-Asn-Ser-Lys-Cys-Pro-Asp-Gly-Pro-Asp-Cys-Phe-Val-Gly-Leu-Met-
NH2. This is a sequence identical to that of the tachykinin scyliorhinin
II. Perfusion of synthetic scyliorhinin II increased secretion rate in the
rectal gland of S. canicula in a dose-dependent manner with a maximal
response at 10(-6) M, whereas vasoactive intestinal peptide, a stimulator
in the spiny dogfish, Squalus acanthias, had no effect. We propose that
scyliorhinin II is the uncharacterized peptide rectin, previously
identified from the intestine of S. canicula.
