A minimal model using stable isotopes to study the metabolism of apolipoprotein B-containing lipoproteins in humans.
A protocol using stable isotopes, developed to measure apolipoprotein B turnover in humans, was tested by intravenous infusion of [2H3]-leucine into 5 normolipidemic volunteers during a 14-h fast. Tracer-to-tracee ratio curves were analyzed by four different approaches: linear regression, monoexponential regression, a minimal compartmental model (3 compartments) and a complex model (4 compartments and two shunt pathways). The three-compartment model was validated by qualitative analysis of data obtained after injection of a [2H3]-leucine bolus. This simple model gave an FCR of 0.48 +/- 0.05 h-1 for VLDL, 0.62 +/- 0.08 h-1 for IDL and 0.022 +/- 0.002 h-1 for LDL. The total production rate of apolipoprotein B in plasma was 24.8 +/- 6.5 mg.kg-1.day-1. Kinetic parameters were similar for the complex model which showed no improvement in fit. Lower estimates were observed with the non-compartmental approaches.
Maugeais
C
C
Centre de Recherche en Nutrition Humaine, Hôpital G. et R. Laënnec, Nantes, France.
Ouguerram
K
K
Krempf
M
M
Maugeais
P
P
Gardette
J
J
Bigot
E
E
Magot
T
T
D000328:Adult; D000704:Analysis of Variance; D001055:Apolipoproteins B / Q000032:analysis*; D003903:Deuterium; D005215:Fasting / Q000097:blood; D006801:Humans; D007262:Infusions, Intravenous; D007700:Kinetics; D016014:Linear Models; D008074:Lipoproteins / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D012016:Reference Values
D001055:Apolipoproteins B; D008074:Lipoproteins; D003903:Deuterium