AJP - Endocrinology and Metabolism, Vol 244, Issue 5 513-E516, Copyright © 1983 by American Physiological Society
Incorporation of radioactive phospholipid into subclasses of high-density lipoproteins
A. R. Tall, C. B. Blum and S. M. Grundy
The incorporation of orally administered phospholipid into plasma
high-density lipoproteins (HDL) was studied in three subjects. Plasma was
analyzed by equilibrium density gradient ultracentrifugation, 5, 6, and 8 h
after ingestion of 1.1 g [3H-choline, 14C-dilinoleoyl]phosphatidylcholine.
At all time points in all subjects, there was a peak of phosphatidylcholine
specific activity in fractions of density approximately 1.10-1.13 g/ml,
corresponding to the subclass previously designated HDL2a. There was also a
more variable, smaller peak of specific activity of phospholipids in HDL2b
(1.063-1.100 g/ml) and in fractions of density approximately 1.19 g/ml. In
the 1.10-1.13 fraction, 97 and 71%, respectively, of the 3H and 14C
radioactivity were in phospholipids. The 3H/14C ratio was similar in
phospholipids of HDL subfractions, the d less than 1.07 fraction, and in
the administered phospholipid. The results show preferential transfer or
exchange or absorbed phosphatidylcholine into specific subclasses of HDL.
