Abstract
Plasma immunoreactive glucagon and insulin levels were determined during and following the intravenous infusion of 1-arginine in normal non-obese and obese subjects, and patients with various endocrine diseases and chronic liver diseases. After overnight fasting and absolute bed rest for at least 30 min, patients and normal subjects received an intravenous infusion of 30g of 1-arginine over a period of 45min.
Blood was withdrawn before and then again 5, 10, 15, 20, 30, 45, 60, 90 and 120min after the start of the infusion. Plasma insulin was measured by the double antibody technique of Hales and Randle, and plasma glucagon was determined by the radioimmunoassay method of Sakurai and Imura, with antiserum 30K which is specific for pancreatic glucagon.
In normal subjects, plasma insulin rose significantly within the first 5min of the infusion period and the peak levels occurred at the end of the infusion; plasma glucagon also showed biphasic curves, with the first peak occuring within 10min and the second peak at 45min.
In obese subjects and patients with chronic hepatitis, plasma insulin and glucagon responses arginine to were significantly exaggerated. Patients with Cushing's syndrome, had elevated basal glucagon levels, an d their response to arginine was 300% greater than in normal subjects.
Hyperthyroid patients were characterized by low plasma insulin response and almost normal plasma glucagon response to arginine, whereas hypothyroid patients showed high insulin and glucagon responses.
The significance and pathogenesis of abnorma: plasma insulin and glucagon responses to arginine in these diseases are still obscure at present and must await further clarification.
