Chow S L, Hollander D
J Lipid Res. 1979 Mar;20(3):349-56.
Linoleic acid absorption was studied using everted rat jejunal sacs. At low concentrations (42-1260 microM), the relationship between linoleic acid concentration and its absorption rate fitted best to a rectangular hyperbola. At high concentrations (2.5-4.2 mM) the relationship between the two parameters was linear. The separate additions of 2,4-dinitrophenol, cyanide, or azide, or decrease in the incubation temperature from 37 to 20 degrees C did not change the absorption rate of linoleic acid. Absorption rate of linoleic acid at low concentrations increased as the hydrogen ion and taurocholate concentrations were increased or as the unstirred water layer thickness was decreased. Linoleic acid absorption rate was decreased after the additions of lecithin, oleic, linolenic, and arachidonic acids or the substitution of taurocholate with the nonionic surfactant Pluronic F 68. These observations indicate that a concentration-dependent, dual mechanism of transport is operative in linoleic acid absorption. Facilitated diffusion is the predominant mechanism of absorption at low concentrations, while at high concentrations, simple diffusion is predominant. At low concentrations, the absorption rate of linoleic acid is influenced by the pH, surfactant type and concentration, the simultaneous presence of other polyunsaturated fatty acids, and the thickness of the unstirred water layer.
利用外翻大鼠空肠囊研究了亚油酸的吸收情况。在低浓度（42 - 1260微摩尔）时，亚油酸浓度与其吸收率之间的关系最符合矩形双曲线。在高浓度（2.5 - 4.2毫摩尔）时，这两个参数之间的关系呈线性。单独添加2,4 - 二硝基苯酚、氰化物或叠氮化物，或将孵育温度从37℃降至20℃，均未改变亚油酸的吸收率。低浓度时亚油酸的吸收率随氢离子和牛磺胆酸盐浓度的增加或未搅动水层厚度的减小而增加。添加卵磷脂、油酸、亚麻酸和花生四烯酸后，或用非离子表面活性剂普朗尼克F 68替代牛磺胆酸盐后，亚油酸的吸收率降低。这些观察结果表明，亚油酸吸收存在一种浓度依赖性的双重转运机制。在低浓度时，易化扩散是主要的吸收机制，而在高浓度时，简单扩散占主导。在低浓度时，亚油酸的吸收率受pH值、表面活性剂类型和浓度、其他多不饱和脂肪酸的同时存在以及未搅动水层厚度的影响。
