The metabolism of apolipoproteins (a) and B-100 within plasma lipoprotein (a) in human beings

Abstract The metabolism of apolipoproteins (apo) (a) and B-100 within plasma lipoprotein (a) [Lp(a)] was examined in the fed state in 23 subjects aged 41 to 79 years who received a primed-constant infusion of [5,5,5- 2 H 3 ] leucine over 15 hours. Lipoprotein (a) was isolated from the whole plasma using a lectin affinity-based method. Apolipoprotein (a) and apoB-100 were separated by gel electrophoresis, and tracer enrichment of each apolipoprotein was measured using gas chromatography/mass spectrometry. Data were fit to a multicompartmental model to determine fractional catabolic rates (FCRs) and secretion rates (SRs). The FCRs of apo(a) and apoB-100 (mean ± SEM) within plasma Lp(a) were significantly different (0.220 ± 0.030 pool/d and 0.416 ± 0.040 pool/d, respectively; P P r = 0.837 and r = 0.789, respectively; P r = −0.547 and r = −0.717, respectively; P