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Regulation of lung surfactant cholesterol metabolism by serum lipoproteins
Author(s) -
Hass Michael A.,
Longmore William J.
Publication year - 1980
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/bf02534063
Subject(s) - cholesterol , lipidology , chemistry , metabolism , reverse cholesterol transport , lipoprotein , clinical chemistry , medicine , cholesteryl ester , endocrinology , pulmonary surfactant , intermediate density lipoprotein , lung , biochemistry , low density lipoprotein , very low density lipoprotein , high density lipoprotein , perfusion , biology
The isolated perfused rat lung was used as an experimental model in the study of the lipoprotein regulation of surfactant cholesterol metabolism. Addition of low density lipoproteins (LDL) to the perfusion medium at a cholesterol concentration of 0.5 mM had no inhibitory effect on [1‐ 14 C]‐acetate incorporation into cholesterol of either the surfactant or residual fractions. Increasing the concentration of cholesterol in the medium to 2.5 mM resulted in significant inhibition of incorporation into cholesterol of both fractions. A similar inhibition resulted when lungs were perfused with 2.5 mM cholesterol in the form of high density lipoproteins (HDL). No inhibition of fatty acid synthesis, measured as incorporation into cholesteryl esters, was observed. The rate of uptake by perfused lung of cholesterol from both high and low density lipoproteins was similar. Competitive binding studies with 125 I‐labeled lipoproteins indicated the existence of lung receptors for both classes of lipoprotein. The rate of uptake of the apoprotein moiety of low density lipoproteins was significantly greater than that of high density lipoproteins. These data suggest that lung cholesterol metabolism may be subject to regulation by both low and high density serum lipoproteins.