[Relationship between exercise-induced changes in serum and hepatic cholesterol metabolism in rats]

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 assigned 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 less than 0.01) for the total cholesterol and 10% and 24% (p less than 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 HMG-CoA reductase activity was negatively related to serum total (r = -0.62, p less than 0.01) and HDL (r = -0.58, p less than 0.01) cholesterol levels. From these results, we concluded that the enhancement of the cholesterol metabolism in the liver by exercise is a major course of the exercise-induced change in serum cholesterol of Wistar rats.