TY - JOUR
T1 - Distribution of apolipoprotein A-IV between the lipoprotein and the lipoprotein-free fractions of rat plasma
T2 - Possible role of lecithin:Cholesterol acyltransferase
AU - DeLamatre, J. G.
AU - Hoffmeier, C. A.
AU - Lacko, A. G.
AU - Roheim, P. S.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1983
Y1 - 1983
N2 - Plasma samples were incubated under various conditions to study the effect of in vitro incubation on apolipoprotein A-IV distribution between the lipoprotein and lipoprotein-free fractions. When plasma was fractionated immediately after bleeding, apolipoprotein A-IV was present in equal concentrations in the lipoprotein and lipoprotein-free fractions. After a 4-hr, 37°C incubation, >90% of total plasma apolipoprotein A-IV was present in the lipoprotein fraction and the percentage of plasma cholesterol present as cholesteryl ester increased from 58% to 74%. When plasma was incubated for 4 hr at 37°C in the presence of 1.5 mM 5,5-dithiobis(2-nitrobenzoic acid) (DTNB), >90% of total plasma apoA-IV was present in the lipoprotein-free fraction, whereas plasma cholesteryl ester concentration did not change. Incubating heat-inactivated plasma for 4 hr also resulted in the redistribution of apolipoprotein A-IV from the lipoprotein fraction to the lipoprotein-free fraction, concurrent with no change in cholesterol esterification. When heat-inactivated plasma was incubated in the presence of a purified lecithin:cholesterol acyltransferase preparation, cholesterol esterification was restored and apolipoprotein A-IV was redistributed from the lipoprotein-free fraction to the lipoprotein fraction in such a manner that >90% was present in the lipoprotein fraction. No changes in apolipoprotein A-I and apolipoprotein E distributions were found under any of the above conditions. Thus, the in vitro plasma incubations show that apolipoprotein A-IV can move bidirectionally between lipoprotein and lipoprotein-free fractions; the direction of this movement depends on the condition of the incubation. These data also suggest that the LCAT reaction can influence apolipoprotein A-IV distribution in the plasma.
AB - Plasma samples were incubated under various conditions to study the effect of in vitro incubation on apolipoprotein A-IV distribution between the lipoprotein and lipoprotein-free fractions. When plasma was fractionated immediately after bleeding, apolipoprotein A-IV was present in equal concentrations in the lipoprotein and lipoprotein-free fractions. After a 4-hr, 37°C incubation, >90% of total plasma apolipoprotein A-IV was present in the lipoprotein fraction and the percentage of plasma cholesterol present as cholesteryl ester increased from 58% to 74%. When plasma was incubated for 4 hr at 37°C in the presence of 1.5 mM 5,5-dithiobis(2-nitrobenzoic acid) (DTNB), >90% of total plasma apoA-IV was present in the lipoprotein-free fraction, whereas plasma cholesteryl ester concentration did not change. Incubating heat-inactivated plasma for 4 hr also resulted in the redistribution of apolipoprotein A-IV from the lipoprotein fraction to the lipoprotein-free fraction, concurrent with no change in cholesterol esterification. When heat-inactivated plasma was incubated in the presence of a purified lecithin:cholesterol acyltransferase preparation, cholesterol esterification was restored and apolipoprotein A-IV was redistributed from the lipoprotein-free fraction to the lipoprotein fraction in such a manner that >90% was present in the lipoprotein fraction. No changes in apolipoprotein A-I and apolipoprotein E distributions were found under any of the above conditions. Thus, the in vitro plasma incubations show that apolipoprotein A-IV can move bidirectionally between lipoprotein and lipoprotein-free fractions; the direction of this movement depends on the condition of the incubation. These data also suggest that the LCAT reaction can influence apolipoprotein A-IV distribution in the plasma.
UR - http://www.scopus.com/inward/record.url?scp=0021031679&partnerID=8YFLogxK
M3 - Article
C2 - 6668451
AN - SCOPUS:0021031679
SN - 0022-2275
VL - 24
SP - 1578
EP - 1585
JO - Journal of Lipid Research
JF - Journal of Lipid Research
IS - 12
ER -