The role of adrenergic receptors in the increased glucose uptake by the canine gut.

The study was carried out on fasted anaesthetized dogs. A vein draining a segment of the upper jejunum was cannulated for blood flow measurement. Arterial blood and venous blood from the upper jejunal segment, were obtained for measurement of glucose content. Glucose uptake was calculated as the product of jejunal blood flow and the difference between arterial and venous glucose levels. Prazosin, (0.2 mg/kg) had no effect on the glucose uptake induced by insulin and glucagon injections and glucose infusion. However, prazosin reduced the glucose uptake by about 50% during adrenaline-induced hyperglycaemia. Pretreatment of the animal with propranolol (0.5 mg/kg) significantly reduced the increased glucose uptake caused by adrenaline, glucagon and glucose hyperglycaemia. Propranolol also reduced by half the negative glucose uptake during insulin-hypoglycaemia. Since both the alpha and beta adrenergic receptor blocking agents did not abolish the induced glucose uptake, it was concluded that the effects of adrenaline, glucagon, glucose and insulin on intestinal glucose uptake are mediated in part by beta adrenergic receptors.