Immunoreactive glucagon in nondiabetic and diabetic Macaca nigra

The primary form of immunoreactive glucagon (IRG) in Macaca nigra has been identified as pancreatic, alpha-cell-size glucagon (IRG3500), with a molecular weight of about 3500. Assays with 30K and K-964 glucagon antibodies gave virtually identical results. Column chromatography of plasma on Bio-Gel P-30 indicated ony minimal amounts of high-molecular-weight IRG. Levels of IRG decrease during a glucose infusion, a response expected of IRG3500. IRG concentrations apparently greater than human values appear to be characteristic of nonhuman primates. Nondiabetic Macaca nigra average 641 pg of IRG3500/ml. Borderline diabetic monkeys with moderately increased glucose and impaired glucose clearance average 2,938 pg/ml. Diabetic monkeys with hyperglycemia and diminished glucose clearance have 375 pg of IRG3500/ml. Changes in IRG3500 are related to a lesion in the islets of Langerhans.