Abstract
The effects of disopyramide on insulin secretion were studied by perfusing the isolated rat pancreas in situ. In experiments carried out using Krebs-Ringer bicarbonate buffer containing 0.1% glucose (0.1% glucose buffer), the immunoreactive insulin (IRI) levels in the perfusate did not change after the administration of disopyramide (300μg/0.1 ml, i.c.a.). When Krebs-Ringer bicarbonate buffer containing 0.3% glucose (0.3% glucose buffer) was substituted, IRI levels increased significantly after the disopyramide administration. The disopyramide-induced IRI rise was not affected by pretreatment with propranolol, phentolamine or atropine. The increase of insulin secretion induced by increasing glucose concentration from 0.1% to 0.3% in the perfusion fluid was suppressed by disopyramide. The suppressing action of disopyramide on glucosestimulated insulin secretion was partially recovered after pretreatment with propranolol or phentolamine. Results show that disopyramide acts both as a stimulator and an inhibitor of insulin secretion.
