Progastrin-like immunoreactivity in porcine antrum: identification and characterization with region-specific antisera.
In an effort to identify and characterize precursors of gastrin in tissues, we generated region-specific antisera against a synthetic progastrin peptide, Try-Gly-Trp-Met-Asp-Phe-Gly-Arg-Arg (GL9), as deduced from the nucleotide sequence of gastrin mRNA. This antisera did not cross-react with gastrin or progastrin peptides with shorter carboxyl-terminal extensions. Progastrin-like immunoreactivity (PGLI) was measured in porcine antrum at a concentration of 6.8 +/- 1.2 pmol/g wet weight (mean +/- SE, n = 5), or roughly 0.2% of that of gastrin. On Sephadex G50 chromatography, a major peak of PGLI was eluted as a slightly larger molecule than gastrin heptadecapeptide (G17) but possessed the same N-terminal immunoreactivity. These findings suggest that G17 may be formed by processing of a carboxyl-terminally extended precursor as an alternative to cleavage of big gastrin (G34).
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D002850:Chromatography, Gel; D003429:Cross Reactions; D005755:Gastrins / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D007106:Immune Sera; D011498:Protein Precursors / Q000032:analysis / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis; D013270:Stomach / Q000032:analysis; D013552:Swine
D005755:Gastrins; D007106:Immune Sera; D011498:Protein Precursors; D012333:RNA, Messenger; C013706:big gastrin