Plasma lipoproteins and cholesterol metabolism in spontaneously hyperlipemic rats.
The aim of this study was to characterize the plasma lipoprotein pattern and some aspects of cholesterol metabolism in a line of hyperlipemic male rats. Plasma cholesterol and triglycerides were increased about 3-fold as compared to control animals (238 vs. 75 and 185 vs. 59 mg/dl respectively). The plasma lipoprotein distribution and the chemical composition of the isolated lipoproteins was unaffected. Plasma triglyceride production rate was increased (40%, P less than 0.01) and post-heparin lipoprotein lipase activity in plasma decreased (-28%, P less than 0.01) in the hyperlipemic rat. The activity of 3 enzymes involved in cholesterol metabolism (HMG-CoA reductase, cholesterol 7 alpha-hydroxylase, and acyl-CoA cholesterol-acyltransferase) did not differ from control values. 3H2O incorporation into digitonin-precipitable sterols, however, was significantly higher than in controls. This finding was due, in part, to an increased liver weight in the hyperlipemic animals. Furthermore kinetic data using 125I-LDL showed that the fractional catabolic rate of lipoprotein was within the normal range, while the synthetic rate of LDL protein was increased (0.67 vs. 0.3 mg/kg/h, P less than 0.01) in the hyperlipemic rat. These observations suggest that multiple metabolic defects underline the hyperlipemia observed in this animal model.
Fantappiè
S
S
Institute of Pharmacological Sciences, School of Pharmacy, University of Milan, Italy.
Crestani
M
M
Bosisio
E
E
Galli
G
G
Maggi
F M
FM
Corsini
A
A
Catapano
A L
AL
D000818:Animals; D002784:Cholesterol / Q000378:metabolism*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D006949:Hyperlipidemias / Q000201:enzymology / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism*; D008954:Models, Biological; D051381:Rats; D011919:Rats, Inbred Strains; D002785:Sterol O-Acyltransferase / Q000378:metabolism
D008077:Lipoproteins, LDL; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases; D002790:Cholesterol 7-alpha-Hydroxylase; D002785:Sterol O-Acyltransferase