[The effect of vigorous exercise training on cholesterol metabolism in rats]

Twenty-eight male Wistar rats, aged 7 weeks, were subjected to a vigorous exercise regimen of running for 5 weeks and 35 rats were selected as their controls. After 5 weeks both exercised and control rats were injected 2 microCi of 14C-mevalonate per 100 g body weight into peritoneal cavities and sequentially sacrificed at 20, 40, 60, 80, 100, 120, and 180 min after the injections in each subgroup. The exercised rats showed a significantly lower level of serum total cholesterol than the control rats. The activity of HMG-CoA reductase in liver microsome was significantly higher in the exercised rats than in the control rats. No differences existed in intestinal HMG-CoA reductase activity between exercise and control groups. The incorporation of mevalonate into liver cholesterol and serum cholesterol (especially HDL fraction) in the exercised rats were significantly higher compared with these of the control. Furthermore, the exercised rats showed a higher rate of cholesterol synthesis activity in liver. From these results it was concluded that the hepatic lipoprotein cholesterol production was elevated by exercise compared with that of control.