BESTIMMUNG DER INSULINAKTIVITÄT IM SERUM UNBEHANDELTER JUGENDLICHER DIABETIKER NACH GLUKOSEBELASTUNG

Abstract

As a continuation of earlier experiments we have determined the insulinlike activity (ILA) in the serum of newly-found, untreated juvenile diabetics before and after oral loading with glucose. This has been done by the method of glucose-1-C14 oxidation to C14O2 on the rat epididymal adipose tissue. Each value was calculated from the mean values of 6 individual results. In some of these diabetics, the glucose uptake of the rat diaphragm was also investigated at the same time. The fasting values of the "total" ILA of the untreated juvenile diabetics were found to be 150% higher than in normal subjects and this was confirmed statistically. In contrast to normal subjects glucose loading did not lead to an increase but, after 60 and 120 minutes, to a continual significant decrease of the ILA to 60 and 53% of the starting value, while the blood sugar was markedly increased. As in normal subjects the fasting values of the "free" ILA as determined on the rat diaphragm were low and amounted only to about one tenth of the "total" ILA. Sixty minutes after glucose loading, however, the "free" ILA increased to 57% above the starting value and this was confirmed statistically. Thus in newly-found, untreated juvenile diabetics a large quantity of insulin is found in the blood and this insulin is obviously present in a biologically inactive form. A small part can be released by an extreme increase in the blood sugar concentration. An insulin reserve is no longer detectable.