[Effects of aerobic exercise on regulation of activities of hepatic low density lipoprotein receptor in hypercholesterolemic rats].

The present study is to determine the effects of exercise on the regulatory role in activities of hepatic low density lipoprotein receptor (LDL-R) in experimental hypercholesterolemic (HC) rats. Using a specific assay for the binding of 125I-LDL receptor to homogenate, the activity of hepatic LDL-R were measured. It was observed that the activity of LDL-R in HC decreased by 37% as compared with the normal control (NC) rats. HC rats also had a higher levels of serum total cholesterol (TC), LDL-Cholesterol (LDL-C) and apolipoprotein B (Apo B). The rats fed on high-cholesterol diet combined with exercise for 12 weeks (HE) had lower TC, LDL-C and Apo B levels than those of HC rats, and had a higher hepatic LDL-R activity which was 26% higher than that of HC rats. These finding suggested: (1) LDL-R activity may be regulated downward in cholesterol-loaded rats; (2) Exercise may enhance the utilization and degradation of intracellular cholesterol, and may have a feedback effect on the down-regulated synthesis of LDL-R, thus increase the uptake of LDL-C and lower plasma level of lipid.