Vitamin A metabolism in the human intestinal Caco-2 cell line.
Vitamin A metabolism in the human intestinal Caco-2 cell line.
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DOI：
10.1021/bi00502a015
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发表时间：
1990-12
期刊：
影响因子：
2.9
通讯作者：
Timothy C. Quick;D E Ong
中科院分区：
文献类型：
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作者：
Timothy C. Quick;D E Ong
人类肠道 Caco-2 细胞系在许多研究中被描述为肠上皮细胞样，对其进行吸收过程中通常所需的维生素 A 代谢的能力进行了检查。 Caco-2 细胞含有细胞视黄醇结合蛋白 II，这是一种在人绒毛相关肠细胞中丰富的蛋白质，可能在维生素 A 的吸收中发挥重要作用。Caco-2 细胞的微粒体制剂含有视网膜还原酶、酰基辅酶 A 视黄醇酰基转移酶 (ARAT) 和卵磷脂-视黄醇酰基转移酶 (LRAT) 活性，此前已提出这些活性参与肠上皮细胞中膳食维生素 A 的代谢。当向完整的 Caco-2 细胞提供 β-胡萝卜素、乙酸视黄酯或视黄醇时，会合成视黄酯棕榈油酸酯、油酸酯、棕榈酸酯和少量硬脂酸酯。然而，Caco-2 细胞并未使用外源视黄醇棕榈酸酯或硬脂酸酯作为酯合成的视黄醇来源。虽然与人乳糜微粒中常见的视黄酯或大鼠肠道中通常合成的酯相比，Caco-2 细胞中视黄醇单烯脂肪酸酯的合成不成比例，但该模式与 Caco-2 微粒体磷脂酰胆碱（LRAT 的脂肪酰基供体）的 sn-1 位置中发现的大量不饱和脂肪酸一致，特别是 18:1 和 16:1。 ARAT 和 LRAT 均被认为负责肠细胞中视黄酯的合成。（摘要截断为 250 字）
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) activities, 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 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.(ABSTRACT TRUNCATED AT 250 WORDS)