The carboxamide feG(NH2) inhibits endotoxin perturbation of intestinal motility.

The submandibular gland rat-1 (SMR1) salivary gland prohormone contains several peptides, submandibular gland peptide-T (SGP-T) and the tripeptide, FEG, which possess anti-inflammatory activities. The D-isomeric form of FEG, feG, also is a potent anti-inflammatory peptide. In this study, we compared the inhibitory activity of feG and its carboxamide derivative, feG(NH2), on the perturbations of intestinal motility induced by intravenous lipopolysaccharide. feG(NH2) was 20-30 times more potent than feG in reducing the motility disturbances induced by lipopolysaccharide. feG may undergo square-amidation to yield a hormone that strongly down-regulates intestinal responsiveness to endotoxin.