The metabolic response to norepinephrine in normal versus diabetic man

Summary Norepinephrine was infused for 60 minutes in high physiological concentration (0.08 μg/ kg/min) into seven insulin dependent diabetic subjects with no demonstrable endogenous insulin secretion and into seven normal subjects. Insulin dependent diabetic subjects had a stable, free insulin concentration of 23±5 μU/ml which was unaffected by norepinephrine infusion. In the normal subjects, norepinephrine induced an initial inhibition of insulin secretion which lasted for approximately 20 minutes. Norepinephrine infusion caused a rapid increase in both ketone body and glucose concentrations but this response did not differ between the two groups. In contrast, plasma nonesterified fatty acid and triglyceride concentrations were increased significantly more in the normal than in the diabetic subjects. The increase in plasma glucagon concentrations was similar in the two groups of subjects. The cause of the differential metabolic response to norepinephrine between the normal and diabetic groups was not resolved, but may be related, at least in part, to suppression of endogenous insulin secretion in the normal subjects.