Chromatographic pattern of gut glucagon-like immunoreactivity (GLI) in plasma before and during glucose absorption

In this work we have studied the chromatographic pattern on Bio-Gel P-30 columns of the glucagon-like immunoreactivity (GLI) present in unextracted plasma from normal dogs in the basal state and after intraduodenal administration of glucose. Basal plasma GLI, measured by R-8 antiserum, was distributed in four distinct fractions, whose approximate molecular weights were: greater than 30000 delta (Fraction I), 10000 delta (Fraction II), 3500 delta (Fraction III) and 2000 delta (Fraction IV). Fraction I accounted for the highest percent of total immunoreactivity. The increase in plasma GLI during glucose absorption was due to a significant increase of Fraction II, which may well correspond to tissue GLI Peak I, while no significant changes were evident in the other three fractions. The fact that tissue Peak I (or plasma Fraction II) ssems to be the factor secreted during glucose absorption puts the material/s of this molecular size in the first place for further investigation.