Arginine-stimulated hyperglucagonemia in diabetic Pima Indians

Groups of 27 nondiabetic Pima Indians, 34 nondiabetic Caucasians, and 12 diabetic Pima Indians with recent onset of their disease received an arginine infusion to determine if (1) nondiabetic Pima Indians and Caucasians had a similar glucagon response to arginine and (2) diabetic Pimas had excessive glucagon response to arginine as reported in other racial groups. The fasting glucagon levels in the three groups were not significantly different. During arginine monochloride infusion (5 mg./kg./minute for 40 minutes) the diabetic Pimas had glucagon levels significantly higher at 10 minutes and at all sampling points thereafter than the normo-glycemic Pimas. Plasma insulin levels also increased during the infusion but, notably, never differed significantly between these two groups. There was no significant difference in the glucagon levels at any sampling point between the nondiabetic Pimas and Caucasians. The differences in glucagon levels between the nondiabetic and diabetic Indians are similar to those differences reported between diabetic and nondiabetic subjects of other racial origins.