A comparison of two methods to investigate the metabolism of human apolipoproteins A-I and and A-II.
Two methods are compared for measuring the kinetic parameters of apolipoprotein A-I and A-II metabolism in human plasma. In the first, high density lipoprotein apoproteins were radioiodinated in situ in the lipoprotein particle (endogenous apoprotein labeling) while in the second, individually labeled apolipoprotein A-I or A-II was incorporated into the particle by in vitro incubation (exogenous apoprotein labeling). The catabolic clearance rate of exogenously labeled apolipoprotein A-I was consistently faster than that of endogenous apolipoprotein A-I. Conversely, endogenously and exogenously labeled apolipoprotein A-II were catabolized at identical rates. The fractional plasma clearance rates of endogenous apolipoproteins A-I and A-II were the same.
D000328:Adult; D001053:Apolipoproteins / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods; D008075:Lipoproteins, HDL / Q000378:metabolism*; D008297:Male; D011863:Radioimmunoassay; D014461:Ultracentrifugation
D001053:Apolipoproteins; D007457:Iodine Radioisotopes; D008075:Lipoproteins, HDL