pH dependent gastrin secretion mechanism: an immunocytochemical study

Abstract

Gastrin secretion is induced by vagal stimuli, local distension, peptides or aminoacid solutions, and Ca2+ concentration both in stomach lumen and blood. However, the cellular and molecular mechanisms of gastrin-release are unknown. We have tested the effects of different pH fixative solutions on gastrin distribution by the immunolabeling of antral gastrin cells (G cells).Samples from different portions of adult dog digestive tract and related glands (salivary glands, liver and pancreas) were embedded in paraffin by conventional methods. Another samples from the antral mucosa of adult dogs and rats were fixed using mixtures of glutaraldehyde and paraformaldehyde at different pH (from 4 to 7,6 pH), and embedded in araldite and Unicryl. For post-embedding immnunocytochemical staining purposes, sections were incubated with pre - diluted policlonal rabbit anti-human gastrin (Zimed Labs.Inc., San Francisco, USA), rinsed in TBS and incubated with a 15 nm gold-conjugated IgG as secondary antibody. These sections were stained with uranil acetate and examined with TEM.