Identification and expression of prohormone converting enzymes in
the rat stomach.
Macro, Janet A., Rod Dimaline, Graham J. Dockray.
The Physiological Laboratory, University of Liverpool, Liverpool,
U.K.
APStracts 2:0141G, 1995.
The conversion of regulatory peptide precursors to their active forms
usually involves limited proteolysis which may be mediated by
subtilisin-like prohormone convertases (PC). We have examined the
representation of this enzyme family in rat gastric mucosa. Using PCR
employing primers to conserved sequences, we identified from rat
antrum clones corresponding to PC1/3, PC2, PC5 and furin. Northern
blots indicated that the mRNA's for PC1/3, and PC2 were substantially
more abundant in mucosa compared with muscle, and that there were
differences in expression in antrum and corpus. In the antrum a PC1/3
probe identified bands of 3 and 4.5kb that were of equal intensity
and were both increased in fasted rats; in corpus the latter mRNA
species predominated, and did not change with fasting. In rats
treated with omeprazole, there was a preferential increase in the
antral 3kb band. In both antrum and corpus a PC2 probe hybridized
with a band of 2.8 kb that increased in omeprazole-treated rats. The
data suggest that (a) PC1/3 and PC2 are expressed in antral mucosa
and so are candidates for gastric regulatory peptide processing, (b)
there is selective processing of the mRNA's encoding prohormone
convertases in different gastric cell populations, and (c) the
expression of these enzymes is physiologically regulated.
Received 31 January 1995; accepted in final form 30 June 1995.
APS Manuscript Number G45-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 18 July 1995.