Lipoprotein kinetics in patients with analbuminemia. Evidence for the role of serum albumin in controlling lipoprotein metabolism.
In vitro data suggested that albumin is a key factor controlling apolipoprotein (apo) synthesis by hepatocytes. Studies in analbuminemic rats have shown an increase in secretion of apoB-containing lipoprotein from the liver. We studied the kinetic aspects of apoB- and apoAI-containing lipoprotein metabolism in two sisters with analbuminemia using a constant 14-hour infusion of leucine labeled with stable isotopes. Compared with control subjects, total cholesterol was higher in the two patients (432 and 461 versus 155 +/- 14 mg/dL), as was apoB (257 and 230 versus 72 +/- 7 mg/dL). Triglycerides were slightly increased (134 and 105 versus 89 +/- 9 mg/dL), whereas apoAI was lower (109 and 105 versus 124 +/- 6 mg/dL). VLDL-apoB production was higher, as was the production of IDL-apoB and LDL-apoB (32.8 and 36.0 versus 24.8 +/- 5.9, 32.1 and 27.2 versus 16.4 +/- 2.3, and 14.1 and 17.6 versus 10.3 +/- 1.2 mg.kg-1.d-1, respectively). The fractional catabolic rate of all the apoB-containing lipoproteins was decreased (0.23 and 0.37 versus 0.48 +/- 0.05, 0.27 and 0.28 versus 0.62 +/- 0.08, and 0.012 and 0.009 versus 0.022 +/- 0.002.h-1, respectively). A similar mechanism could explain the dyslipidemia observed in other conditions associated with low albumin levels, such as nephrotic syndrome.
Maugeais
C
C
Centre de Recherche en Nutrition Humaine, Hôpital G. & R. Laĕnnec, Nantes, France.
Braschi
S
S
Ouguerram
K
K
Maugeais
P
P
Mahot
P
P
Jacotot
B
B
Darmaun
D
D
Magot
T
T
Krempf
M
M
D000328:Adult; D016632:Apolipoprotein A-I / Q000378:metabolism; D053299:Apolipoprotein B-100; D001055:Apolipoproteins B / Q000378:metabolism* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000209:etiology*; D008074:Lipoproteins / Q000378:metabolism*; D053419:Lipoproteins, IDL; D008077:Lipoproteins, LDL / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000378:metabolism; D008297:Male; D012044:Regression Analysis; D012709:Serum Albumin / Q000172:deficiency*; D014280:Triglycerides / Q000378:metabolism
D016632:Apolipoprotein A-I; D053299:Apolipoprotein B-100; D001055:Apolipoproteins B; D008074:Lipoproteins; D053419:Lipoproteins, IDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D012709:Serum Albumin; D014280:Triglycerides