Effects of gosha-jinki-gan, a kampo medicine, on peripheral tissue blood flow in streptozotocin-induced diabetic rats.

We examined the effects of Gosha-jinki-gan on peripheral tissue blood flow in streptozotocin-induced diabetic rats and its mechanism. The decrease in peroneal muscular blood flow in diabetic rats was dose-dependently improved by treatment with Gosha-jinki-gan (0.1-1 g/kg/day, p.o.) for 4 weeks. Investigation of the time course of blood flow in the hind paws revealed that single-dose of Gosha-jinki-gan (0.3, 1.5 g/kg, i.d.) increased peripheral blood flow. Peripheral blood flow-increasing effects of Gosha-jinki-gan (1.5 g/kg, i.d.) were reduced in combination with atropine (1 mg/kg, i.v.), and disappeared by pretreatment with NG-nitro-L-arginine methyl ester (10 mg/kg, i.v.). Levels of aortic guanosine 3',5'-cyclic monophosphate were dose-dependently increased by administration of Gosha-jinki-gan (0.3, 1.5 g/kg, p.o). These results suggest that Gosha-jinki-gan has vasodilating effects via increases in nitric oxide production. Gosha-jinki-gan may be useful for treating peripheral circulation disorders in the diabetic state.