Osiecka I, Cortese M, Porter P A, Borchardt R T, Fix J A, Gardner C R
J Pharmacol Exp Ther. 1987 Aug;242(2):443-9.
The mechanism of intestinal uptake of alpha-methyldopa (Aldomet) was investigated using isolated segments of rat small intestine. Incubations were limited to 2 to 5 min as histological examination of the tissue showed significant loss of structural integrity after 10 to 20 min at 37 degrees C. alpha-Methyldopa in the tissue was extracted and assayed by high-pressure liquid chromatography. Corrections were applied for uptake into extracellular spaces using inulin (14C). Uptake was temperature- and concentration-dependent (Km congruent to 10 mM), was dependent on the location in the small intestine and was inhibited by ouabain (2 mM) or lack of sodium or glucose in the incubation medium. alpha-Methyldopa uptake also was inhibited by other neutral amino acids. The mucosal cell layer accounted for approximately 50% of the total drug accumulated in the tissue. Uptake was less when the serosal surface was exposed than when the tissue was everted. The similarity in uptake parameters between alpha-methyldopa and L-phenylalanine (parallel experiments) suggests that alpha-methyldopa is principally absorbed into rat small intestinal mucosal cells via an amino acid transport system.
使用大鼠小肠分离段研究了α-甲基多巴（爱道美）的肠道摄取机制。由于组织学检查显示，在37℃下孵育10至20分钟后，组织的结构完整性显著丧失，因此孵育时间限制在2至5分钟。组织中的α-甲基多巴通过高压液相色谱法提取和测定。使用菊粉（14C）对细胞外空间的摄取进行校正。摄取是温度和浓度依赖性的（Km约为10 mM），取决于小肠中的位置，并且在孵育介质中被哇巴因（2 mM）或缺乏钠或葡萄糖所抑制。α-甲基多巴的摄取也被其他中性氨基酸抑制。粘膜细胞层约占组织中积累的总药物的50%。当浆膜表面暴露时，摄取比组织外翻时少。α-甲基多巴和L-苯丙氨酸之间摄取参数的相似性（平行实验）表明，α-甲基多巴主要通过氨基酸转运系统吸收到大鼠小肠粘膜细胞中。
