The effect of epinephrine on immunoreactive insulin levels in man.

The mechanisms by which epinephrine elevates the blood sugar have been of considerable interest for more than 25 years. In an extensive review in 1956, Ellis suggested that the two major in- fluences on glucose metabolism were increased glycogenolysis in the liver and peripheral tissues, and direct inhibition of glucose uptake by muscle (1). There is, however, the additional possibility that epinephrine might decrease insulin levels. The introduction of insulin immunoassay (2, 3) has allowed us to examine this third hypothesis in man. Our data show that epinephrine infusion is not associated with a rise in serum immunoreactive insulin (IRI) despite significant hyperglycemia. In addition, epinephrine was found to inhibit the expected rise in IRI after administration of ex- ogenous glucose, glucagon, and tolbutamide.