Serum Immunoreactive Insulin Response During Prolonged Glucose Infusions in Nondiabetic and Diabetic Humans

Prolonged intravenous glucose infusions were employed to study pancreatic islet cell reserve, measured by responses in serum immunoreactive insulin levels. A continuous intravenous glucose load (6 gm./kg./24 hrs.) was administered for five to seven days to four nondiabetic subjects and five maturity-onset diabetic patients. The nondiabetics assimilated all the glucose, but the diabetics developed marked hyperglycemia and glucosuria. Immunoreactive insulin levels were similar in the two groups, and insulin response to eating breakfast daily during the infusions was at least as high in the diabetics as in the nondiabetics. During these infusions, there was no evidence that the diabetic patients differed from the nondiabetic controls by showing progressive decreases in serum immunoreactive insulin responses.