Effects of cholesterol supplementation on antioxidant enzyme activities in rat hepatic tissues: possible implications of hepatic paraoxonase in atherogenesis

Nutr Metab Cardiovasc Dis. 2004 Aug;14(4):211-4. doi: 10.1016/s0939-4753(04)80007-3.


Background and aim: The effects of cholesterol supplementation on antioxidant enzyme activities were investigated hepatic tissue taken from Sprague Dawley rats. METHODS AND REULTS: The study involved 14 male Sprague Dawley rats: seven fed a normal laboratory diet and seven a normal diet plus cholesterol (3.6 g/kg/day) for three months, during which blood samples were obtained to measure serum cholesterol levels. At the end of the 3-month period, the livers were surgically removed in order to measure antioxidant enzyme activities (superoxide dismutase, catalase, glutathione peroxidase and paraoxonase-1). At the end of the study period, serum total cholesterol and HDL-cholesterol levels were significantly higher in the cholesterol-fed group than the control group. There were no significant between-group differences in hepatic superoxide dismutase, catalase and glutathione peroxidase activities, but there was a significant decrease in hepatic paraoxonase-1 activity in the cholesterol-fed group.

Conclusions: Cholesterol supplementation significantly decreases paraoxonase-1 activity in rat liver tissue without changing the activities of other antioxidant enzymes. These results suggest that cholesterol significantly suppresses hepatic paraoxonase-1 synthesis. It seems that the decreased paraoxinase-1 activity in the plasma HDL-fraction of atherosclerotic patients is associated with suppressed liver synthesis. A reduction in paraoxonase-1 activity may therefore lead to the more intensive exposure of LDL to oxidant attacks.

MeSH terms

  • Animals
  • Arteriosclerosis / drug therapy
  • Arteriosclerosis / metabolism
  • Aryldialkylphosphatase / biosynthesis
  • Aryldialkylphosphatase / drug effects
  • Aryldialkylphosphatase / metabolism*
  • Catalase / metabolism
  • Cholesterol / blood
  • Cholesterol, Dietary / administration & dosage*
  • Cholesterol, HDL / blood
  • Dietary Supplements
  • Glutathione Peroxidase / metabolism
  • Liver / enzymology*
  • Male
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Superoxide Dismutase / metabolism


  • Cholesterol, Dietary
  • Cholesterol, HDL
  • Cholesterol
  • Catalase
  • Glutathione Peroxidase
  • Superoxide Dismutase
  • Aryldialkylphosphatase