Gastric fundic inhibition of sugar transport across the intestinal mucosa of guinea-pig.

A low molecular weight peptide designated gastric fundic factor (GFF), extracted from porcine fundic mucosa and administered to the serosal surface of mucosal sheets from guinea-pig intestine, decreased the transport of luminal glucose across the sheets by up to 70%. The results show that gastric fundic inhibition of glucose absorption observed in different animal models in vivo can be reproduced in vitro, and suggest that the intestinal mucosa itself is the target for peptide hormone(s) released by the gastric fundic mucosa. Simultaneous transport of alpha-aminoisobutyric acid, a nonmetabolisable amino acid, through the jejunal mucosa was unaffected as was paracellular permeation by inulin. However, amino acid transport was also reduced when GFF was administered to sheets of ileal mucosa. The intestinal mucosal sheet in vitro is a sensitive and convenient model with which to follow the purification of GFF to homogeneity.