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Uptake and metabolism of dolichol and cholesterol in perfused rat liver
Author(s) -
Kalén A.,
Söderberg M.,
Elmberger P. G.,
Dallner G.
Publication year - 1990
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02562211
Subject(s) - dolichol , cholesterol , microsome , endoplasmic reticulum , lipidology , clinical chemistry , chemistry , biochemistry , metabolism , phosphatidylcholine , reverse cholesterol transport , cytoplasm , medicine , membrane , phospholipid , in vitro , lipoprotein , biosynthesis , enzyme
The uptake of dolichol and cholesterol by perfused rat liver was studied. When these radioactive lipids were incorporated into egg phosphatidylcholine liposomes, both dolichol and cholesterol appeared initially in the supernatant and in the microsomal fraction and, later on, in the mitochondrial‐lysosomal fraction. The lipids taken up were esterified to some extent, but no phosphorylation of dolichol occurred. Incorporation of dolichol and cholesterol into lipoproteins increased the efficiency of uptake, which was receptor‐mediated in this case. Accumulation of these lipids occurred in lysosomes followed by a transport to the endoplasmic reticulum (ER). Both labeled dolichol and cholesterol appeared in the bile. In the case of dolichol, the majority of this radioactivity was not associated with the original substance itself, and probably represented lipid‐soluble catabolites. In the case of cholesterol, most of the radioactivity was associated with bile acids. It appears that, in contrast to the receptor‐mediated uptake of lipoproteins from the perfusate, the uptake of liposomal lipids involves a different mechanism. After association with the plasma membrane, the lipids enter into the cytoplasm and are transported to the ER and later to the lysosomes.