HYDROXYL RADICAL FORMATION IN DIABETIC RATS INDUCED BY STREPTOZOTOCIN

Production of hydroxyl radicals was examined in the diabetic rats indu ced by streptozotocin to prove its involvement to the pathogenesis of diabetes. Hydroxyl radicals generated in plasma, heart muscle, liver a nd brain of the hyperglycemic rats were quantitatively assayed by trap ping hydroxyl radicals with salicylic acid as 2,3- and 2,5-dihydroxybe nzoic acid. The concentrations of 2,3- and 2,5-dihydroxybenzoic acid w ere significantly increased in all the tissues of the diabetic rats. I n the brain and heart muscle of the diabetic rats, the increase of 2,3 -dihydroxybenzoic acid was more manifest than that of 2,5-dihydroxyben zoic acid, while in liver 2,5-dihydroxybenzoic acid increased markedly . All the values of 2,3-dihydroxybenzoic acid detected in the tissues of the diabetic rats were quite higher than those in control. Hydroxyl radical production and blood glucose concentration were depended almo st linearly on the amount of streptozotocin injected to rats up to 60 mg/kg body weight. It was suggested that 2,3-dihydroxybenzoic acid was produced from hydroxyl radicals themselves, while 2,5-dihydroxybenzoi c acid was produced by hydroxylation of salicylic acid not only with h ydroxyl radicals, but also by enzymatic reaction of microsomal cytochr ome-P450. Hydroxyl radical formation may account for some pathological process especially in the heart muscle and brain.