The association between plasma GIP and insulin after oral glucose.

The correlation between the peripheral concentrations of gastric inhibitory polypeptide (GIP), insulin, and glucose has not previously been quantified. This paper describes the association among the peripheral concentrations of GIP, insulin and glucose during 50-g oral glucose tolerance tests (OGTT) in healthy volunteers and in patients with gastrointestinal disorders, obesity, and uremia. It was found that the correlation between insulin/glucose and plasma GIP concentrations during an OGTT can be expressed by the equation: log y = log a + bx, where y = [insulin]/[glucose], and x is the plasma GIP concentration. This empirical correlation between [insulin]/[glucose] and [GIP] reduces the plasma parameters measured during OGTT to a simple relationship. It may prove valuable in the analysis of differences in the relationship glucose-insulin-GIP between groups of subjects and in the description of alterations in glucose homeostasis longitudinally in individuals undergoing therapy.