The purpose of the present study was to determine the effects of exercise training on serum cholesterol level and hepatic cholesterol metabolism in rats. Twenty-four male Wistar strain rats, aged 6 weeks, were assigued to one of three experimental groups ; control (n=8), exercised 20 minutes a day (E20, n=8), and exercised 60 minutes a day (E60, n=8). Rats were sacrificed after ten weeks exercise. The levels of serum total cholesterol and HDL-cholesterol in the group E20 and group E60 were lower than that of control, 8% and 24% (p<0.01) for the total cholesterol and 10% and 24% (p<0.05) for the HDL-cholesterol, respectively. The activity of HMG-COA reductase in liver microsome was significantly higher in the group E60 than that of control. The hepatic microsomal HivlG-CoA reductase activity was negatively related to serum total (r= -0.62, p<0.01) and HDL (r= -0.58, p<0.01) cholestrol levels. From these results, we concluded that the enhancement of the cholesterol metabolism in the liver by exercise is a major couse of the exercise-induced change in serum cholesterol of Wistar rats.
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