Nonimmunochemical quantitation of mammalian apolipoprotein A-I in whole serum or plasma by nonreducing gel...

A rapid and convenient method for the quantitation of mammalian apoA-I has been developed. The method involves nonreducing sodium dodecyl sulfate gel electrophoresis and Coomassie blue staining, and takes advantage of the relative abundance of apoA-I in whole serum or plasma. ApoA-I was sufficiently resolved to allow quantitation by laser densitometry or spectrophotometry. The assay was linear from 0.25 to 4.0 micrograms of apoA-I. Analytic recovery was 98%. Within-assay variability was 3.1% and between-assay variability was 7.5%. A high degree of positive correlative (r = 0.98) was observed with a human apoA-I radioimmunoassay. For several species investigated, the apoA-I values obtained correlated strongly and positively with high density lipoprotein cholesterol values. When applied to a study of nutritional perturbation in the Mongolian gerbil, the method detected sensible and significant changes in serum apoA-I that paralleled changes in HDL cholesterol.