Effects of diltiazem on insulin level in rats

AIM: The effects of calcium antagonist diltiazem on plasma insulin levels were investigated in rats. METHODS: Plasma insulin was measured with radioimmunoassay method. RESULTS: In the fasting rat, plasma insulin levels were significantly increased after ig diltiazem 10 mg · kg_-1 and 100 mg · kg_-1, and the level of plasma insulin was increased by 131% 30 min after administration of diltiazem 100 mg · kg_-1 in comparison with that of control group. Diltiazem increased the plasma insulin level markedly in glucose tolerance test of the rat. In the hyperglycemia rat induced by adrenaline, diltiazem 100 mg · kg_-1 weakly increased the plasma insulin level only at 1 h after administration. CONCLUSION: Diltiazem increases the plasma insulin levels in the fasting rat and glucose-loaded rat. The increase of plasma insulin level induced by diltiazem is due to the hyperglycemic action of diltiazem and other effect, probably a direct or an indirect insulin-release-action on pancreas of the rat.