Infusion of diazoxide (16.5 mg./kg. in 10 minutes) into normal unanesthetized dogs resulted in a prompt hyperglycemia due to increased hepatic glucose production as measured with a 3-3H-glucose primer-infusion technique. Plasma insulin and gtucagon were decreased. Glucose uptake failed to increase. Diazoxide administration during period of alpha adrenergic receptor blockade with phentolamine still caused hyperglycemia and increased glucose production. Glucose uptake was inhibited despite adequate plasma insulin. Infusion of somatostatin along with insulin prevented the effects of diazoxide on plasma glucose and glucose production.

It is concluded that diazoxide hyperglycemia is not due solely to decreased insulin secretion or increased epinephrine secretion and that gtucagon is not a contributory factor. Diazoxide may act directly to increase glucose production and inhibit glucose uptake. Somatostatin appears capable of blocking the effect of diazoxide on glucose production by an unknown mechanism.