The binding of rat LDL and rabbit β-VLDL to liver plasma membranes of copper-deficient rats was examined. Characterization experiments demonstrated binding of both lipoprotein fractions to be relatively insensitive to treatment with pronase, EDTA, excess CaCl2, or heparin. Competitive displacement experiments demonstrated that the binding reaction is not dependent on specific apolipoprotein ligands and imply a nonspecific binding site. These results indicate binding independent of the LDL or chylomicron remnant receptor. Copper deficiency had no effect on the total binding of either LDL or β-VLDL over a wide range of label concentration. The data indicate that hepatic membranes from copper-deficient rats do not exhibit altered binding capacity for LDL or β-VLDL and provide evidence that an impairment in receptor-mediated binding of lipoproteins does not contribute to the hypercholesterolemia observed in copper-deficient rats.
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Supported by funds from the 86-CRCR-1-1925.
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- in vitro