RESUMO
ObjectiveTo investigate the effect of hyperglycemia on calcium load and cyclic AMP content in normal and STZdiabetic rat skeletal muscle.MethodsCalcium load and cyclic AMP content were measured in vivo and in vitro after incubation with 5.6mmol/L and 16.7mmol/L glucose concentration.Atom spectrum absorption assay for calcium and radioimmunoassay for cAMP were employed.ResultsHigh concentration glucose elevated cyclic AMP content and lessened calcium load significantly.Cyclic AMP also elevated in diabetic skeletal muscle incubated with even 5.6mmol/L glucose.Diabetes was necessary for high concentration glucose to elevate cyclic AMP in vitro,because cyclic AMP did not change in normal rat muscle even incubated with 16.7mmol/L glucose.But diabetes discounted the reduction of calcium load induced by 16.7mmol/L glucose.ConclusionThe effects of hyperglycemia on calcium load and cyclic AMP content in skeletal muscle may accord with its antiinsulin action,which may be involved in the mechanism of glucose toxicity.