Vitamin A metabolism in the human intestinal Caco-2 cell line

Journal Article · Sat Dec 01 00:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00502a015· OSTI ID:5475068

Quick, T C; Ong, D E ^[1]

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1. Vanderbilt Univ. School of Medicine, Nashville, TN (USA)

The human intestinal Caco-2 cell line, described as enterocyte-like in a number of studies, was examined for its ability to carry out the metabolism of vitamin A normally required in the absorptive process. Caco-2 cells contained cellular retinol-binding protein II, a protein which is abundant in human villus-associated enterocytes and may play an important role in the absorption of vitamin A. Microsomal preparations from Caco-2 cells contained retinal reductase, acyl-CoA-retinol acyltransferase (ARAT), and lecithin-retinol acyltransferase (LRAT) activites, which have previously been proposed to be involved in the metabolism of dietary vitamin A in the enterocyte. When intact Caco-2 cells were provided with {beta}-carotene, retinyl acetate, or retinyl acetate, or retinol, synthesis of retinyl palmitoleate, oleate, palmitate, and small amounts of stearate resulted. However, exogenous retinyl palmitate or stearate was not used by Caco-2 cells as a source of retinol for ester synthesis. While there was a disproportionate synthesis of monoenoic fatty acid esters of retinol in Caco-2 cells compared to the retinyl esters typically found in human chylomicrons or the esters normally synthesized in rat intestine, the pattern was consistent with the substantial amount of unsaturated fatty acids, particularly 18:1 and 16:1, found in the sn-1 position of Caco-2 microsomal phosphatidylcholine, the fatty acyl donor for LRAT. Both ARAT and LRAT have been proposed to be responsible for retinyl ester synthesis in the enterocyte. These data suggest the LRAT may be the physiologically important enzyme for the esterification of retinol in Caco-2 cells.

• OSTI ID: 5475068
• Journal Information: Biochemistry; (USA), Vol. 29:50; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
MEMBRANE PROTEINS
RADIOIMMUNOASSAY
TUMOR CELLS
ENZYME ACTIVITY
VITAMIN A
METABOLISM
CARCINOMAS
CHOLINE
DOSE-RESPONSE RELATIONSHIPS
INTESTINES
IODINE 125
MAN
MICROSOMES
RETINOIC ACID
TRANSFERASES
ALCOHOLS
AMINES
AMMONIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOASSAY
BODY
CARBOXYLIC ACID ESTERS
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
ESTERS
GASTROINTESTINAL TRACT
HYDROXY COMPOUNDS
IMMUNOASSAY
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIPOTROPIC FACTORS
MAMMALS
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PRIMATES
PROTEINS
QUATERNARY COMPOUNDS
RADIOASSAY
RADIOIMMUNODETECTION
RADIOIMMUNOLOGY
RADIOISOTOPES
RIBOSOMES
TRACER TECHNIQUES
VERTEBRATES
VITAMINS
550601* - Medicine- Unsealed Radionuclides in Diagnostics