胆汁酸对维甲酸抑制α-生育酚吸收的逆转作用。

Reversal by bile acid on the inhibition of alpha-tocopherol absorption by retinoic acid.

作者信息

Bieri J G, Tolliver T J

出版信息

J Nutr. 1982 Feb;112(2):401-3. doi: 10.1093/jn/112.2.401.

DOI:10.1093/jn/112.2.401

Abstract

This study explores several possible mechanisms by which dietary retinoic acid may cause the previously described reduced intestinal absorption of alpha-tocopherol. Measurement of fecal excretion of rats showed that dietary retinoic acid caused twice as much alpha-tocopherol to be excreted as when retinol was the source of vitamin A. Excretion was the same for free and esterified alpha-tocopherol, thus, the retinoic acid effect originally observed was not due to impaired hydrolysis of the ester. There was no effect of retinoic acid on triglyceride absorption. Collection and analysis of bile from rats fed either form of vitamin A showed no difference in bile volume or bile acid composition. The addition of 0.2% taurocholic acid to the diet, however, reversed the effect of retinoic acid on tocopherol absorption. In vitro studies of mixed micelles containing 3H-alpha-tocopherol and retinoic acid or retinol showed no difference in size due to the form of vitamin A in the micelles.

摘要

本研究探讨了膳食视黄酸可能导致先前所述的α-生育酚肠道吸收减少的几种可能机制。对大鼠粪便排泄的测量表明，与视黄醇作为维生素A来源时相比，膳食视黄酸导致α-生育酚的排泄量增加了一倍。游离型和酯化型α-生育酚的排泄情况相同，因此，最初观察到的视黄酸效应并非由于酯水解受损所致。视黄酸对甘油三酯的吸收没有影响。对喂食任一形式维生素A的大鼠胆汁进行收集和分析，结果显示胆汁量或胆汁酸组成没有差异。然而，在饮食中添加0.2%的牛磺胆酸可逆转视黄酸对生育酚吸收的影响。对含有3H-α-生育酚和视黄酸或视黄醇的混合胶束进行的体外研究表明，胶束中维生素A的形式对胶束大小没有影响。