Endurance training increased HDL cholesteryl ester metabolism in rats

We studied the effects of endurance training on the metabolism of high-density lipoprotein (HDL, 1.063 less than density less than 1.15 kg/l) cholesteryl ester and proteins in rats fed a cholesterol-rich (1%) semipurified diet. The HDL were labeled with 131I in the apoproteins and with cholesteryl-[1-14C]oleate in the esters. The HDL were intravenously administered to endurance-trained (n = 10) and cage-sedentary (n = 10) rats. Blood samples were taken over the next 36 h while the rats were conscious and feeding. The trained rats had higher plasma HDL cholesterol (0.72 vs. 0.28 mM) and HDL apoprotein (461 vs. 267 mg/l) concentrations than the sedentary rats. The production or disposal rate of HDL cholesteryl ester was higher in the trained rats (1.36 mumol/h) than in the sedentary rats (0.72 mumol/h), whereas the production or disposal rate of HDL apoproteins was similar in the trained (0.64 mg/h) and sedentary (0.60 mg/h) rats. The residence time of the HDL cholesteryl esters (4.72 +/- 0.22 vs. 3.37 +/- 0.21 h) and HDL apoprotein (7.65 +/- 0.36 vs. 4.55 +/- 0.28 h) was longer for the trained than for the sedentary rats. These data indicate that endurance training resulted in a significant change in the metabolism of HDL cholesteryl esters and apoproteins as well as an increase in their concentrations.