No evidence for feedback inhibition of hepatic apolipoprotein B (apo B) production after extracorporeal low density lipoprotein precipitation as determined by [1-13C]leucine infusion in normal volunteers.
To determine the impact of an acute reduction of the circulating mass of apolipoprotein B (apo B) on apo B metabolism we studied six healthy male volunteers before (day 0), 1 day after (day 2), and 7 days after (day 8) an LDL apheresis treatment which reduced apo B mass by 59%. Appearance of newly synthesized apo B in plasma VLDL and LDL was studied using a primed-constant infusion of [1-13C]-leucine. VLDL apo B pool size and fractional VLDL apo B production rate calculated using a one-compartment model were similar on all 3 study days. Absolute VLDL apo B production was not statistically different throughout the study (19.7 +/- 12.3, 19.5 +/- 7.5, 29.1 +/- 17.7 mg kg-1 day-1). LDL apo B fractional production rate was increased on day 2 (0.38 +/- 0.17, 0.68 +/- 0.08, 0.37 +/- 0.06 pools day-1 on days 0, 2, and 8; P < 0.01). Absolute LDL apo B production, however, remained constant throughout the study (10.8 +/- 3.3, 11.0 +/- 1.9, 10.8 +/- 3.1 mg kg-1 day-1). We conclude that in healthy male volunteers acute reduction of the circulating apo B mass by LDL apheresis does not affect apo B metabolism significantly.
Arends
J
J
Metabolism Division, Washington University School of Medicine, St. Louis, MO.
Bier
D M
DM
Schäfer
G
G
Armstrong
V W
VW
Thiery
J
J
Seidel
D
D
Schauder
P
P
D000328:Adult; D001055:Apolipoproteins B / Q000096:biosynthesis*; D002784:Cholesterol / Q000097:blood; D005246:Feedback / Q000502:physiology; D006801:Humans; D007553:Isotope Labeling; D007930:Leucine / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000302:isolation & purification*; D008079:Lipoproteins, VLDL / Q000032:analysis; D008099:Liver / Q000378:metabolism*; D008297:Male; D008954:Models, Biological; D014280:Triglycerides / Q000097:blood
D001055:Apolipoproteins B; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D014280:Triglycerides; D002784:Cholesterol; D007930:Leucine