INSULIN PATTERNS PRIOR TO AND AFTER ONSET OF DIABETES

In two of three adults in whom responses to an oral glucose load were studied before and after diabetes had appeared, the increases in serum insulin in response to an oral glucose load taken during the diabetic phase were definitely greater than those recorded before the diabetes appeared. Thus, in two patients the ratio of the increment in blood sugar to the increment in insulin recorded after glucose intolerance had appeared was lower than that documented one year earlier during the pre-diabetic phase, indicating an enhanced insulin response. In other words, a true hyperinsulinemia relative to the rise in blood sugar was present in these two persons with newly-discovered diabetes. The enhanced glucose-induced hyperinsulinemia in these newly-discovered diabetic persons indicates that in them the diabetes stemmed from inadequacy of hypoglycemic action of the insulin either because the insulin molecule was defective, pro-insulin was present, insulin action was vitiated by plasma or tissue antagonism, or absorption of glucose was enhanced. The finding of diminished insulin increments in relation to increases in blood sugar following an oral glucose load in one other adult with diabetes of one year's duration or less suggests that this may be another pattern in some diabetic persons. Alternatively, it is possible that the true hyperinsulinemia noted in our other two patients is a transient phase which may disappear within a year. In the one child in this series, fasting and postglucose hyperinsulinemia was present during the prediabetic phase relative to the insulin responses recorded in control studies in nondiabetic children. After diabetes had developed and prior to any therapy, an oral glucose load did not evoke a rise in serum insulin. © 1969.