Effects of Diabetes on Glucose Oxidation in Rat Aorta after Hypophysectomy and Adrenalectomy

Summary

The influence of diabetes, hypophysectomy and adrenalectomy on glucose oxidation in rat aorta was studied. Diabetes was induced in normal, adrenalectomized and hypophysectomized-cortisone substituted rats by streptozotocin (65 mg/kg body weight). The oxidation of glucose to CO₂ was determined during incubation of rat aorta in vitro for 2-3 hours.

The aortic glucose oxidation was reduced after hypophyslectomy but was unaffected by adrenalectomy. After streptozotocin treatment the rise in blood glucose concentration was similar in normal, adrenalectomized and hypophysectomized-cortisone substituted rats. In shamoperated diabetic rats and hypophysectomized-cortisone substituted diabetic rats the aortic glucose oxidation was reduced after a diabetes duration of 4 days. In adrenalectomized diabetic rats the aortic glucose oxidation was not significantly affected after 4 days but was reduced after a diabetes duration of 14 days. When adrenalectomized diabetic rats were treated with hydrocortisone the aortic glucose oxidation was reduced after diabetes for 4 days.

After incubation of normal rat aorta in vitro for 6 hours with cortisol (1 μg/ml) in the incubation medium a decrease in the aortic glucose oxidation was found. Incubation of aorta with only growth hormone had no effect.

These results suggest that cortisol is of importance for the lowered glucose oxidation in diabetic rat aorta.

Key-Words:

Diabetes Mellitus - Rat Aorta - Vascular Smooth Muscle - Glucose Oxidation - Adrenalectomy - Hypophysectomy - Cortisol - Growth Hormone - Streptozotocin