Copper deficiency in rats raises plasma cholesterol concentration while reducing liver cholesterol concentration. One consequence of this cholesterol redistribution is the accumulation of a large high-density lipoprotein (HDL) particle rich in apolipoprotein E (apo E). The purpose of this study was to determine, using an in vitro binding assay, if the interaction of apo E-rich HDL with hepatic lipoprotein binding sites may be affected by copper deficiency. Male Sprague-Dawley rats were divided into two dietary treatments (copper-deficient and -adequate) and placed on a dietary regimen for 8 weeks. Subsequent to exsanguination, hepatic plasma membranes were prepared and apo E-rich HDL was isolated from rats of each treatment by ultracentrifugation, agarose column chromatography, and heparin-Sepharose affinity chromatography. Total binding and experimentally derived specific binding of 125I-apo E-rich HDl to hepatic plasma membranes indicated greater binding when lipoproteins and membranes from copper-deficient animals were used in the assay compared to controls. Scatchard analysis of specific binding data indicated that equilibrium binding affinity (Kd) was also affected by copper deficiency. The hepatic binding sites recognizing apo E-rich HDL were not affected by EDTA or pronase, of relatively high capacity, and recognized a variety of other rat lipoproteins.
|Number of pages
|Proceedings of the Society for Experimental Biology and Medicine
|Published - Mar 1988
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology