Heparin-Released Plasma Lipase Activities, Lipoprotein and Apoprotein Levels in Young Adult Cyclists and Sedentary Men

Abstract

Serum lipid and lipoprotein levels, apolipoproteins A-l and B, and lipolytic enzyme activities were studied in 14 young male cyclists and in 21 age-matched sedentary controls.

While there were no significant differences in serum cholesterol between the two groups, the cyclists showed a significant decrease in serum triglycerides (P < 0.05) and LDL cholesterol (P < 0.05) and had significantly higher levels of HDL cholesterol (P < 0.01) and HDL₂ cholesterol (P < 0.001). Significantly lower serum cholesterol/HDL cholesterol (P < 0.001) and LDL cholesterol/HDL cholesterol (P < 0.001) ratios and a significantly higher HDL₂ cholesterol/HDU cholesterol ratio (P < 0.001) were observed in the athletes. Serum apolipoprotein B was lower and the Apo B/Apo A-l ratio significantly reduced in the athletes. No significant differences emerged between the two groups in plasma post-heparin lipoprotein lipase activity (LPL) and in hepatic triglyceride lipase activity (HTGL), and there were no correlations between HDL cholesterol and lipolytic enzyme activities.

In conclusion, this cross-sectional study may indicate that an aerobic training program such as cycling is associated with an advantageous lipoprotein pattern; some factors other than lipolytic activity may contribute to increase the HDL cholesterol levels in physical training.

Key words

lipoprotein cholesterol - apoproteins - lipoprotein lipases - cycling