Arvanitakis C, Longnecker M P, Folscroft J
J Lab Clin Med. 1978 Mar;91(3):467-72.
The intestinal absorption of PABA, a member of the vitamin B complex, was characterized in vivo and in vitro in the rat by the segmental intestinal perfusion and everted gut sac technique. Net PABA absorption was directly proportional to substrate concentration, and saturation of absorption did not occur with increasing concentrations of PABA (1 to 50 mM), indicating a nonsaturable process. Jejunal and ileal absorption rates were similar and were not influenced by the presence of glucose or the absence of sodium in the test solution. Similarly, 14C-PABA transport in vitro was nonsaturable and proportional to PABA concentration (0.05, 0.5, 1, 10, and 50 mM). It was not inhibited by ouabain or other PABA analogues such as folic acid and benzoic acid. These studies indicate that PABA, a vitamin B cofactor, is absorbed by a nonsaturable, sodium-independent process, which characterizes passive diffusion and is similar to the absorption of other vitamin B members.
维生素B族成员对氨基苯甲酸（PABA）在大鼠体内和体外的肠道吸收情况，通过肠段灌注和外翻肠囊技术进行了表征。PABA的净吸收与底物浓度成正比，随着PABA浓度（1至50 mM）的增加，吸收并未出现饱和，表明这是一个非饱和过程。空肠和回肠的吸收速率相似，且不受测试溶液中葡萄糖的存在或钠的缺失的影响。同样，体外14C-PABA的转运是非饱和的，且与PABA浓度（0.05、0.5、1、10和50 mM）成正比。它不受哇巴因或其他PABA类似物（如叶酸和苯甲酸）的抑制。这些研究表明，作为维生素B辅助因子的PABA，通过非饱和、不依赖钠的过程被吸收，这是被动扩散的特征，并且与其他维生素B成员的吸收相似。
