Eosinophils in the lamina propria of the rat stomach bind a biotinylated gastrin analog

Abstract

Gastrin is a small peptide known to function as both a stimulator of gastric acid secretion and as a growth factor. Eosinophils are white blood cells which form a part of the body's defenses against invading microorganisms. Douglas et al. have reported staining, using a biotinylated gastrin analog (biotinyl-L-Trp-L-Leu-ß-Ala), of unidentified cells in the lamina propria of the rat fundic stomach. This gastrin analog has been shown to suppress gastric acid secretion in dogs. We here identify the cells binding this analog as eosinophils. We have perfused and fixed small pieces of fundic stomach with 2% paraformaldehyde/0.5% glutaraldehyde in 0.1 M phosphate buffer, pH 7.4 for 1 hour. The tissue was then embedded in 5% agar and 50 ¼m sections were cut on a vibratome. Sections were incubated for 30 min. with 1.63 x 10-6 M biotinylated gastrin analog, rinsed, and exposed to an avidin-biotin-glucose oxidase complex (ABC-GO; Vector).