RESUMO
To evaluate the plasma levels of insulin and glucagon as well as insulin/glucagon molar ratio under the effect of calcium-channel blocker [nifedipine] in adult male albino rats. Adult male albino rats were classified into placebo [acute and chronic] and nifedipine-treated [acute and chronic] groups. The drug groups received nifedipine in recommended daily doses by means of intragastric tubes for three months for the chronic group whereas the acute group received nifedipine in a single dose. Insulin and glucagon were assayed by RIA Kits and insulin/glucagon [I/G] ratio was calculated. A decrease in plasma levels of insulin and an increase in plasma levels of glucagon together with decrease in insulin/glucagon molar ratio were recorded in chronic nifedipine group as compared to placebo group. The calcium-channel blockers have a hyperglycaemic effect which is thought to be time dependent and so a great care must be taken into consideration if these drugs are obliged for the chronic use for diabetic and hypertensive patients and plasma glucose level as well as I/G ratio should be monitored regularly in patients receiving calcium-channel blocker-nifedipine