抄録
Zinc is an essential cofactor for many enzymes, including those that regulate the metabolism of vitamin A and ethanol in the liver. Alcohol dehydrogenase (ADH) is also a metalloenzyme in which zinc acts as a prosthetic group and a stabilizer of the quarternary protein structure. However, the effects of zinc deficiency diet (ZDD) on liver cytosolic ADH activity and the recovery effects from ZDD have not yet been fully elucidated. Therefore, we studied the effect of ZDD and the recovery effects on the liver ADH activity in rats. Four weeks old male Sprague Dawley rats (n=32) were divided into four groups : (a) ZDD (zinc=1.9mg/kg diet) for 26 days, (b) the control group (zinc=53.5mg/kg diet) for 26 days, (c) ZDD diet (zinc=1.9mg/kg diet) for 26 days and then replaced on the zinc supplemented control (zinc=53.5mg/kg diet) for 19 days, and (d) the control group for (c). Liver cytosolic ADH activities were assayed spectrophotometrically at 38°C, and liver cytosolic protein assays were performed by the method of Lowry et al. Liver cytosolic specific ADH activities were significantly reduced to about 1/4, by ZDD for 26 days. However, a significant reduction in the activity of liver cytosolic ADH was recovered to the control levels when zinc intake (zinc=53.5mg/kg diet) of the normal levels was supplemented for consequtive 19 days to the ZDD in rats. These results suggest that liver cytosolic ADH activity in rats regulated by the magnitude of zinc intake. [J Physiol Sci. 2006;56 Suppl:S225]
