In vivo ESR study on hepatic reduction of a nitroxide radical after administration of glucose in rats

The in vivo reducing ability of a nitroxide radical, 4-hydroxyl-2,2,6,6-tet ramethylpiperidin-1-oxyl (TEMPOL), in the liver of rats was estimated by us ing an electron spin resonance spectrometer equipped with a surface-coil-ty pe resonator following administration of glucose. Both oral and intravenous administration of glucose significantly enhanced the reduction capacity, I n vitro studies show that the reduction site of TEMPOL in the hepatic homog enate is located in the mitochondrial respiratory chain and microsomal elec tron transport system. These findings indicate that the enhancement of acti vity of these systems caused by the glucose administration prompts reductio n of TEMPOL in the liver.