Lipoprotein lipase hydrolysis of retinyl ester: possible implications for retinoid uptake by cells

Adipose tissue contains substantial stores of retinoid (retinol + retinyl ester) that, quantitatively, are second only to retinoid stores in the liver. Our studies show that retinoid levels in adipose tissue are markedly influenced by dietary retinoid intake. Because lipoprotein lipase (LPL) increas...

Full description

Saved in:

Bibliographic Details
Published in:	The Journal of biological chemistry Vol. 269; no. 24; pp. 16559 - 16565
Main Authors:	Blaner, W.S, Obunike, J.C, Kurlandsky, S.B, Al-Haideri, M, Piantedos, R, Deckelbaum, R.F, Goldberg, I.J
Format:	Journal Article
Language:	English
Published:	Bethesda, MD American Society for Biochemistry and Molecular Biology 17-06-1994
Subjects:	ACTIVIDAD ENZIMATICA ACTIVITE ENZYMATIQUE Adipocytes - metabolism Adipose Tissue - metabolism Analytical, structural and metabolic biochemistry Animals Biological and medical sciences Biological Transport Cattle Cell Line CELLULE CELULAS Chylomicrons - metabolism Esters - metabolism Female Fundamental and applied biological sciences. Psychology Heterocyclic compounds, pigments HIDROLISIS Humans HYDROLYSE Hydrolysis Lipoprotein Lipase - metabolism LIPOPROTEINA LIPASA LIPOPROTEINE LIPASE Lipoproteins, LDL - metabolism Liver - metabolism Male Milk - enzymology Miscellaneous Other biological molecules RAT RATA Rats Retinoids - metabolism RETINOL Substrate Specificity TEJIDO ADIPOSO TISSU ADIPEUX Vitamin A - blood Vitamin A - metabolism Lipoprotein LDL Adipose tissue Enzymatic activity Enzyme Membrane transport Hydrolases Esterases Lipoprotein lipase Retinoids Triglyceride Carboxylic ester hydrolases Retinol
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Adipose tissue contains substantial stores of retinoid (retinol + retinyl ester) that, quantitatively, are second only to retinoid stores in the liver. Our studies show that retinoid levels in adipose tissue are markedly influenced by dietary retinoid intake. Because lipoprotein lipase (LPL) increases the uptake of lipoproteins and lipid emulsion particles by many cell types including adipocytes, we investigated whether LPL also increases retinoid uptake by adipocytes from lipid-containing particles. Addition of LPL (10 microgram/ml) to BFC-1 beta adipocytes produced a 2-fold increase in cellular uptake of [3H]retinoid from a lipid emulsion containing [3H]retinyl ester. Heparin, which displaces LPL from binding sites on cell surface proteoglycans, increased [3H]retinoid uptake by an additional 2-fold. High performance liquid chromatography analyses showed that greater than 75% of the media and 85% of the cellular radioactivity was present as retinol. The conversion of retinyl ester to retinol by LPL was then assessed using model retinyl ester containing lipid emulsions. Although triglyceride appears to be the preferred substrate for LPL, after greater than 25% of the triglyceride was hydrolyzed, significant amounts of retinyl ester were hydrolyzed by LPL. Retinyl ester hydrolysis was increased approximately 20-fold in the presence of a source of apolipoprotein C-II. The physiologically significant palmitate, stearate, oleate, and linoleate esters of retinol were all hydrolyzed by LPL. When LPL was incubated with [3H]retinyl ester containing rabbit mesenteric chylomicrons and in the presence of heparin and apolipoprotein C-II, the LPL was able to completely hydrolyze the retinyl ester to retinol. Thus, LPL is able to catalyze the hydrolysis of retinyl esters and, through the process of hydrolysis, may facilitate uptake of retinoid by adipocytes
Bibliography:	S20 9504266 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0021-9258 1083-351X
DOI:	10.1016/s0021-9258(19)89425-5