Potentiation of the stimulation action of Theophylline on the insulin secretion by intracellular ca2+ antagonist, TMB-8

ABSTRACT

The role of intracellular Ca 2+ stores with cAMP system in insulin secretion has been elucidated by investigating the effects of an intracellular Ca 2+ antagonist, TMB-8, on the glucose-[8.3 mM] stimulated insulin secretion in the absence and presence of theophylline in isolated perfused rat pancreas. TMB-8 [10 muM] alone had no effect on glucose-stimulated insulin secretion. However, theophylline [10 mM] increased the glucose-stimulated insulin secretion by 4-folds. Simultaneous infusion of TMB-8 [10 muM] with theophylline into the isolated perfused pancreas potentiated the stimulatory action of theophylline by 29%. The results were discussed in relation to the set point concept