Nature of Immunoreactive Gastrin Extracted from Tissues of Gastrointestinal Tract

Abstract

Extracts of mucosa from human antrum, duodenum, and proximal jejunum obtained at surgery and at autopsy contain two immunoreactive components of gastrin, separable on the basis of size and charge. These components exhibit the same characteristics as the two plasma gastrin components identified earlier. The major plasma component (BG) has a less acidic charge and larger molecular size than heptadecapeptide gastrin; the minor plasma component (H-LG) resembles heptadecapeptide gastrin in both respects. H-LG predominates in most extracts of antral mucosa, but the relative abundance of BG increases distally, being the only detectable component (although at very low concentration) in proximal jejunal mucosal extracts. Both components are immunochemically indistinguishable from the two plasma components and from heptadecapeptide porcine gastrin.