Rapid transformation of [3H]cholesteryl ester in rat high-density lipoprotein: in vivo and in vitro studies.
[24,25-3H]Cholesteryl ester-labeled rat high-density and low-density lipoproteins were administered to recipient rats. Following death of the rats, a major portion of the radioactivity in administered [3H]cholesteryl ester-high-density lipoprotein rapidly appeared in less dense [3H]cholesteryl ester-lipoproteins and was isolated with the low-density lipoprotein fraction. The specific activity of the esterified cholesterol in the product lipoproteins found with the low-density lipoproteins exceeded that of the precursor high-density lipoproteins. In vitro, the addition of [3H]cholesteryl ester-high-density lipoprotein to plasma resulted in a five- to six-fold increase in radioactivity recovered in the low-density lipoprotein. These results demonstrate that, under a variety of experimental conditions, isolated high-density lipoprotein particles (both in vitro and in vivo) tend to become larger and less dense. Rapid changes in the density of lipoproteins labeled with [3H]cholesteryl ester must be considered when interpreting physiologic studies using this label.
Goldberg
I J
IJ
Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York.
Rosenfeld
R S
RS
Paul
I
I
Miller
L K
LK
Tiell
M L
ML
D000818:Animals; D002788:Cholesterol Esters / Q000097:blood / Q000378:metabolism*; D007700:Kinetics; D008075:Lipoproteins, HDL / Q000097:blood / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism; D051381:Rats
D002788:Cholesterol Esters; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL