The role of hydrogen translocating shuttles during ethanol oxidation in hepatocytes from euthyroid and hyperthyroid rats.

A quantitative study of the contribution of the malate-aspartate and glycerol-3-phosphate cycles to the translocation of reducing equivalents from cytosol to mitochondria during ethanol oxidation has been made in hepatocytes from euthyroid and hyperthyroid rats. 1. In hepatocytes from euthyroid rats both cycles have an almost equal capacity and their relative contribution to total hydrogen transport to the mitochondria depends on the conditions chosen. 2. In hepatocytes from hyperthyroid rats maximal rates of ethanol oxidation were significantly lower than in hepatocytes from euthyroid rats, even though the capacity of the glycerol-3-phosphate cycle was increased. This was due to a decreased activity of alcohol dehydrogenase.