Ken Horigome

Glucagon response to arginine after treatment of diabetes mellitus.

To investigate the aminogenic glucagon response in diabetes mellitus, arginine infusion tests were carried out on twenty-four diabetic patients before and after treatment. Eleven healthy men served as a control group. Plasma glucagon was measured by radioimmunoassay using an antiserum, G21, specific for pancreatic glucagon. Out of twenty-four patients, five were treated with diet alone, eight with sulfonylurea, and eleven with insulin. In all these diabetic groups, the glucose tolerance improved after treatment for diabetes mellitus, while the insulin response to the glucose did not show any remarkable change. The fasting levels of the plasma glucagon did not differ from that of the normal subjects both before and after treatment. Hyperresponsfveness of the plasma glucagon to arginine infusion was observed in all diabetic groups, in comparison with that of the normal controls. The exaggerated response of the plasma glucagon to arginine was lowered following appropriate treatment in each diabetic group. However, as far as the changes in glucagon area during the arginine test are concerned, the aminogenic hyperresponsiveness of the plasma glucagon was reduced prominently in the diabetic group treated with sulfonylurea. The relationship between the response of glucose and plasma insulin and between glucose and glucagon to arginine was investigated, and the importance of the changes in the insulin:glucagon ratio was emphasized. Moreover, the possibility that long-term administration of a sulfonylurea may reduce an exaggerated glucagon response to arginine was discussed.

Plasma glucagon in insulinoma.

SummaryNine patients with insulinoma were studied in order to investigate glucagon levels in the fasting state and the response of plasma glucagon to tolbutamide and arginine. Fasting plasma glucagon levels were within the normal range in all patients except two cases with malignant insulinoma. Although there was no correlation between blood glucose and plasma glucagon, a significant correlation between plasma glucagon and plasma insulin was observed. No detectable changes were found in glucagon levels during tolbutamide injection. In almost all patients except one an exaggerated response of plasma glucagon was demonstrated during arginine infusion test.