Changes in the plasma lipoprotein-apoproteins of guinea pigs in response to dietary cholesterol.

The major apoproteins from four plasma lipoproteins were isolated from control and cholesterol-fed guinea pigs. Apoproteins were studied by column chromatography, polyacrylamide gel electrophoresis, and amino acid analysis. Dietary cholesterol altered the plasma apolipoproteins mainly by an enrichment in the content of arginine-rich polypeptide (ARP) in all density fractions. This protein had a similar molecular weight (34 000), electrophoretic mobility, amino acid composition, and microheterogeneity as ARP reported in other mammalian species. The estimation of plasma concentration of ARP indicates a higher correlation coefficient with plasma unesterified cholesterol (r = 0.98) compared with cholesterol esters (r = 0.62).