Abstract
Effects of noradrenaline and isoproterenol on insulin secretion in rat pancreas have been studied by means of the in situ perfusion method described previously. Noradrenaline: The insulin secretion from the rat pancreas perfused with the high glucose buffer decreases after the administration of 1 μg/0.1 ml of noradrenaline into the perfusion fluid. These noradrenaline-induced hyposecretions can be reversed by pretreatment with phentolamine (10 μg/ml), while they are potentiated after propranolol (10 μg/ml) pretreatment. Isoproterenol : The insulin secretion from the rat pancreas perfused with the same buffer increases after the administration of 1 μg/0.1 ml of isoproterenol into the perfusion fluid. These isoproterenol-induced hypersecretions are found to be potentiated after pretreatment with phentolamine or propranolol, and atropine (100 μg/ml) pretreatment does not produce any changes in the isoproterenol-induced hypersecretion. These results suggest that the β-receptors on the B-cells stimulate the insulin secretion and the β-receptors on the D-cells decrease them. This communication gives a short discussion of whether α-receptors may be on D-cells or not.
