Effect of sorbin on electrolyte transport in rat and human intestine
Eto, B.; Boisset, M.; Griesmar, B.; Desjeux, J.F.
American Journal of Physiology 276(1): G107-G114
1999
ISSN/ISBN: 0002-9513 PMID: 9886985 Document Number: 510445
Stimulating water absorption in the colon represents an important target to reduce stool output in secretory diarrhea. Recently, a 153-amino-acid peptide was isolated from porcine upper small intestine and purified, taking into account the increase of water absorption in guinea pig gallbladder. Accordingly, this peptide was named sorbin. The aim of the present study was to determine if the COOH-terminal heptapeptide of sorbin (C7-sorbin) participates in the regulation of electrolyte transport in the colon. Different regions (from duodenum to colon) of stripped intestinal mucosa from rats or humans were mounted in Ussing chambers to measure the changes in short-circuit current (DIsc) and net 22Na and 36Cl fluxes (JnetNa and JnetCl) after serosal exposure of 10-7 to 10-3 M C7-sorbin. In fasted rat intestine, C7-sorbin (10-4 M) induced an immediate reduction in Isc in the distal ileum and proximal and distal colon but not in the duodenum and jejunum. In the colon, Isc reduction and JnetNa and JnetCl stimulation were dose dependent (EC50 = 2 10-5 M; at 10-4 M, DIsc = -2.66 ± 0.17 meq.h-1.cm-2) but not in the jejunum. The results indicate that C7-sorbin stimulated NaCl neutral absorption and inhibited electrogenic Cl- in rat and human intestinal epithelia. In addition, the antisecretory effect was essentially observed in the distal part of both rat and human intestine and the magnitude of the proabsorptive effect was directly related to the magnitude of the previously induced secretion. Reprinted by permission of the publisher.