Effects of zinc and cholesterol/choleate on serum lipoproteins and the liver in rats.
The effects of short-term treatment with orally-administered zinc sulphate and/or a mixture of cholesterol/choleate on serum lipoprotein and hepatic enzyme levels were studied. Administration of graded doses of zinc sulphate (20 or 40 mg/kg, as zinc ion) for 5 days, dose-dependently increased serum and hepatic zinc levels but depressed the serum high-density lipoprotein-cholesterol (HDL-C) concentration and liver cytochrome P-450 activity. However, it did not affect hepatic concentrations of malondialdehyde and free beta-glucuronidase. Cholesterol/choleate treatment for 5 days markedly damaged the liver, as reflected by elevations of hepatic concentrations of malondialdehyde (both in the mitochondrial and microsomal fractions) and of free beta-glucuronidase; total cholesterol and low-density lipoprotein-cholesterol in the blood were increased, whereas HDL-C was decreased significantly. Concomitant administration of zinc sulphate with cholesterol/choleate further lowered HDL-C levels, but reversed the high hepatic concentrations of both malondialdehyde and free beta-glucuronidase. The present study indicates that both zinc ions and cholesterol can decrease circulatory HDL-C levels and that zinc protects against cholesterol-induced hepatic damage by reducing lysosomal enzyme release and preventing lipid peroxidation in the liver.
Cho
C H
CH
Department of Pharmacology, Faculty of Medicine, University of Hong Kong.
Chen
S M
SM
Ogle
C W
CW
Young
T K
TK
D000818:Animals; D002784:Cholesterol / Q000097:blood / Q000494:pharmacology*; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003840:Deoxycholic Acid / Q000494:pharmacology*; D006937:Hypercholesterolemia / Q000139:chemically induced*; D008054:Lipid Peroxides / Q000378:metabolism; D008074:Lipoproteins / Q000097:blood*; D008099:Liver / Q000187:drug effects*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology*
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D008054:Lipid Peroxides; D008074:Lipoproteins; D003840:Deoxycholic Acid; D008315:Malondialdehyde; D002784:Cholesterol; D015032:Zinc