Relation between insulin and glucose flux rates in the dog

A constant infusion isotope dilution procedure for measurement of plasma insulin flux rates was performed in acutely eviscerated dogs receiving an infusion of nonlabeled insulin; the calculated rate of insulin flux corresponded closely to that of the administered rate, thus validating the isotope dilution procedure. Flux rates of insulin and glucose were measured simultaneously at different steady levels in intact dogs. There was a linear relationship between plasma insulin concentration and insulin flux rate. In each animal there was also a linear relationship between glucose flux rate and insulin concentration, and between rates of glucose flux and insulin flux, but there was considerable inter-animal variation in the slope of the regression lines.