Compensatory mechanisms governing the concentration of plasma low density lipoprotein.
1986; Elsevier BV; Volume: 27; Issue: 1 Linguagem: Inglês
10.1016/s0022-2275(20)38860-x
ISSN1539-7262
AutoresB. V. Howard, Genshi Egusa, W F Beltz, Y. Antero Kesäniemi, S M Grundy,
Tópico(s)Cancer, Lipids, and Metabolism
ResumoTo evaluate factors regulating the concentrations of plasma low density lipoproteins (LDL), apolipoprotein B metabolism was studied in nine Pima Indians (25 * 2 yr, 191 * 20% ideal wt) with low LDL cholesterol (77 * 7 mg/dl) and apoB (60 * 4 mg/dl) and in eight age-and weight-matched Caucasians with similar very low density lipoprotein (VLDL) concentrations, but higher LDL (cholesterol = 104 + 18; apoB = 82 * 10; P < 0.05).Subjects received autologous '"I-labeled VLDL and '251-labeled LDL, and specific activities of VLDL-apoB, intermediate density lipoprotein (1DL)-apoB, and LDL-apoB were analyzed using a multicompartmental model.Synthesis of LDL-apoB was similar (1224 * 87 mg/d in Pimas vs 1218 * 118 mgld in Caucasians) but in Pimas the fractionalcatabolic rate (FCR) for LDL-apoB was higher (0.48 f 0.02 vs 0.39 * 0.04 d-', P < 0.05).In the Pimas, a much higher proportion of VLDL-apoB was catabolized without conversion to LDL (47 * 3 vs 30 * 5%, P < 0.01).When all subjects were considered together, LDL-apoB concentrations were negatively correlated with both FCR for LDL-apoB (7 = -0.79,P < 0,0001) and the non-LDL pathway (7 = -0.43,P < 0.05).Also, the direct removal (non-LDL) path was correlated with VLDL-apoB production (7 = 0.49, P = 0.03), and the direct removal pathway and FCR for LDL-apoB were correlated (r = 0.49, P = 0.03).aInconclusion, plasma LDL appear to be regulated by both the catabolism of LDL and the extent of metabolism of VLDL without conversion to LDL; both of these processes may be mediated by the apoB/E receptor, and appear to increase in response to increasing VLDL production.-
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