Effect of insulin on glucagon secretion mediated via glucose metabolism of pancreatic A cells in ducks.

A possible action of insulin via glucose metabolism on the pancreatic A cell response to glucose, was studied in ducks. 2-Deoxyglucose, a nonmetabolizable analogue of glucose was used. In normal ducks, the hyperglycaemia induced by 2-deoxyglucose (IV: 0.5 g/kg) resulted in hyperglucagonaemia, while the same degree of hyperglycaemia, induced by glucose infusion (IV injection 25 mg/kg, and infusion 5 mg/kg/min) immediately suppressed glucagon secretion. In diabetic ducks, two days after subtotal pancreatectomy, glucose responsiveness of the A cell was abolished, but could be restored by insulin treatment before (IM 0.2 U/kg insulin + 8 micrograms/kg glucagon every 6 h) and during (IV 3.6 mU/kg + infusion 0.9 mU/kg/min) the glucose test (IV: 0.5 g/kg). The normal response of the A cell to glucose was not observed in diabetic insulin-treated ducks after the administration of 2-deoxyglucose (IV: 0.5 g/kg). These data suggest an inhibitory effect of the metabolism of glucose on the release of glucagon. In addition, the action of insulin on the A cell may be mediated by its effect on glucose metabolism within the A cell.