Sund R B, Lauterbach F
Acta Pharmacol Toxicol (Copenh). 1978 Nov;43(5):331-8. doi: 10.1111/j.1600-0773.1978.tb02275.x.
Tissue uptake and transepithelial permeation of 35S-sulphanilic acid were studied in the isolated guinea pig jejunal mucosa. Methoxy-3H-inulin added simultaneously served as a marker for the extracellular space and permeability of paracellular shunt pathways in the preparation. The uptake of sulphanilic acid from the blood side exceeded that from the luminal side 4--7 fold. The permeation of the acid was strongly correlated to the permeation of inulin. At 5 micrometer and 2.5 mM sulphanilic acid under aerobic conditions, the regression lines for the permeation from lumen to blood pass almost through the origin, while the regression lines for the permeation from blood to lumen intersect the ordinate at a positive Y-value. In anaerobiosis, at 25 mM sulphanilic acid, or with addition of p-toluene sulphonic acid only one regression line is obtained for the permeation in both directions. It is concluded that besides a permeation of sulphanilic acid across inulinpermeable shunt pathways an active transport system exists, which transfers the acid from the blood to the luminal side. This system is saturable, depends on aerobic energy and exhibits mutual inhibition by a structurally related compound. The results are comparable to those previously obtained with cardiac glycosides and quaternary ammonium compounds, in the same preparation. Thus, the intestinal mucosa is able to secrete the same classes of compounds which are secreted by the liver and the kidney.
在离体豚鼠空肠黏膜中研究了35S-磺胺酸的组织摄取和跨上皮渗透。同时添加的甲氧基-3H-菊粉作为细胞外空间标记物以及该制剂中细胞旁旁路途径通透性的标记物。磺胺酸从血液侧的摄取超过从肠腔侧摄取4至7倍。该酸的渗透与菊粉的渗透密切相关。在需氧条件下，当磺胺酸浓度为5微米和2.5毫摩尔时，从肠腔到血液的渗透回归线几乎通过原点，而从血液到肠腔的渗透回归线在正的Y值处与纵坐标相交。在厌氧条件下，当磺胺酸浓度为25毫摩尔时，或者仅添加对甲苯磺酸时，双向渗透仅得到一条回归线。得出的结论是，除了磺胺酸通过菊粉不可渗透的旁路途径渗透外，还存在一个主动转运系统，该系统将酸从血液转运到肠腔侧。该系统是可饱和的，依赖于有氧能量，并受到结构相关化合物的相互抑制。这些结果与之前在相同制剂中用强心苷和季铵化合物获得的结果相当。因此，肠黏膜能够分泌肝脏和肾脏分泌的同一类化合物。
