Document Detail


Serum and intracellular retinol in the equine.
MedLine Citation:
PMID:  7199935     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
1. Serum and intracellular distribution of retinol was determined in equines maintained on four levels of vitamin A intake. 2. The form of retinol transported in serum was determined by gel filtration and chromatography to be a complex of retinol bound to a protein of molecular weight (MW) of approximately 20000, which was in turn complexed probably with prealbumin to yield a complex with a MW of 75000 to 80000. 3. Increasing dietary vitamin A levels enhanced the concentration of lipoprotein-bound retinyl esters in the plasma. 4. Vitamin A in the liver cytosol was found predominantly as retinyl esters in a lipid-protein aggregate of MW approximately 2 X 10(6) and hydrated density of 1.063-1.111. In the kidney and adrenal gland, two lipid-protein entities were found with MW of approximately 1.8 X 10(6) and 1.7 X 10(6) respectively. These fractions contained approximately 40 and 20% lipid respectively and had densities of 1.063-1.111 and approximately 1.21. 5. All lipid-protein aggregates were associated with retinyl palmitate hydrolase activity and guanidine treatment released a 15000 MW material, presumably intracellular retinol-binding protein. 6. Increasing dietary vitamin A enhanced the proportion of retinol in the 1.7 X 10(6) fraction. 7. Findings in equine plasma and liver resemble previous observations in other species. The characterization of two new lipid-protein aggregates in equine kidney and adrenal glands, which have hydrolase activity, may be important in intracellular retinal transport and metabolism, especially in animals subjected to high intakes of vitamin A.
Authors:
D Sklan; S Donoghue
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The British journal of nutrition     Volume:  47     ISSN:  0007-1145     ISO Abbreviation:  Br. J. Nutr.     Publication Date:  1982 Mar 
Date Detail:
Created Date:  1982-06-21     Completed Date:  1982-06-21     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0372547     Medline TA:  Br J Nutr     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  273-80     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Biological Transport
Carboxylic Ester Hydrolases / metabolism
Female
Horses / metabolism*
Palmitates / metabolism
Retinol-Binding Proteins / metabolism
Retinol-Binding Proteins, Plasma
Tissue Distribution
Vitamin A / administration & dosage*,  adverse effects,  analogs & derivatives,  metabolism*
Vitamin A Deficiency / metabolism
Grant Support
ID/Acronym/Agency:
5 S07 RR 5464/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Palmitates; 0/Retinol-Binding Proteins; 0/Retinol-Binding Proteins, Plasma; 11103-57-4/Vitamin A; EC 3.1.1.-/Carboxylic Ester Hydrolases; EC 3.1.1.21/retinol-palmitate esterase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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