Study of the Relationship Between Glucose and Insulin Responses to an Oral Glucose Load in Man

Oral glucose tolerance tests have been performed on 125 patients, and the ensuing changes in plasma glucose and insulin concentrations have been measured. The possible effects of factors which could modify the nature of these responses (obesity, age, sex, family history of diabetes, and indications for performing the tolerance test) have been extensively evaluated. None of these variables were found to have a statistically significant effect on the plasma glucose and insulin responses. Two general relationships between glucose and insulin responses have been defined within the population studied. One, based on the quantitative aspects of the glucose and insulin responses, indicated that there was at first an increase, and then, a decrease in the insulin response to progressive degrees of hyperglycemia. The second relationship was independent of the absolute concentrations of either glucose and insulin, and states that the pattern of glucose response during the three hours of the tolerance test determines the pattern of the insulin response during this same time interval.