[Insulin secretion by isolated rat pancreas as affected by prooxidants; relationship to glutathione release]

Rates of basal and glucose-stimulated insulin and glutathione secretion were studied in experiments with isolated rat pancreas, as were prooxidant effects on these values. The rate of oxidized and recovered glutathione release was found increased at glucose concentration increase to 16.7 mmoles in perfusion solution. Addition of prooxidants (tert-butyl hydroperoxide and Fe2+) in concentrations 10(-4) mole did not change basal insulin secretion but resulted in reduction of glucose-stimulated hormone release. Under such conditions a reduction of the rate of oxidized and recovered glutathione release by the pancreas was observed which was adequate to changed GSH/GSSG ratio in isolated Langerhans' islets. It may be supposed that lipid peroxidation results in changed thiol-disulfide ratio in Langerhans' islets B cells and in reduction of their sensitivity to secretogen effect.