Molecular Forms of Human Enteroglucagon in Tissue and Plasma: Plasma Responses to Nutrient Stimuli in Health and in Disorders of the Upper Gastrointestinal Tract*

A means of estimating human enteroglucagon (glucagon-like immunoreactivity of intestinal origin) in tissues and plasma is described, based on the subtraction of RIA values obtained with the C-terminal-directed glucagon antiserum RCS5 from the total glucagon-like immunoreactivity determined with the N-terminal- to midmolecule-directed glucagon antiserum R59. Gel filtration on Sephadex G-50 of human plasma and extracts of normal human intestine separated the R59 immu-noreactivity into three peaks: a small peak of void volume material, a major peak coeluting with porcine glicentin, and a smaller peak coeluting with pancreatic glucagon. No RCS5 im-munoreactivity was detected in the human gut, except for a small amount constituting less than 2% of the total glucagon-like immunoreactivity in the ileum and rectum only. In extracts of human pancreas, the chromatographic profiles obtained with RCS5 and R59 assays differed from the intestinal patterns, but were identical to each other, giving no evidence of a signi...