AJP - Gastrointestinal and Liver Physiology, Vol 239, Issue 1 30-G38, Copyright © 1980 by American Physiological Society
Mechanism of glucagon-induced intestinal secretion
D. N. Granger, P. R. Kvietys, W. H. Wilborn, N. A. Mortillaro and A. E. Taylor
The effects of local intra-arterial glucagon infusion on transcapilary,
lymphatic, and transmucosal fluid and protein fluxes were studied in
autoperfused segments of cat ileum. The glucagon infusions resulted in a
significant increase in intestinal blood flow, lymph flow, capillary
filtration coefficient, capillary pressure, interstitial volume, and
interstitial fluid pressure. Precapillary resistance and the
pre-to-postcapillary resistance ratio decreased during the glucagon
infusion. The transcapillary oncotic pressure gradient and the osmotic
reflection coefficient were reduced, suggesting that capillary permeability
is significantly increased with glucagon. Ultrastructural analysis of
tissue samples acquired during the infusion of higher doses of glucagon
indicates disruption of the mucosal membrane. An glucagon indicates
disruption of the mucosal membrane. An alteration in mucosal structure is
supported by the appearance of plasma proteins in the secreted fluid. The
results of this study indicate that glucagon-induced intestinal secretion
results from an alteration in capillary fluid balance, i.e., an increased
capillary pressure and permeability.
