Bowman R H, Arnow J, Weiner I M
J Pharmacol Exp Ther. 1978 Jul;206(1):207-17.
2,4,6-Triaminopyrimidine (TAP) has been reported to be a blocker of the cation-specific paracellular conductance pathways of several epithelia. The compound is also known to inhibit sodium transport in the frog skin. Its effects on renal function were studied in clearance experiments in anesthetized rats and in isolated perfused rat kidneys and compared with the effects of amiloride. The effects of both compounds on electrical resistance of the frog gallbladder were also evaluated. Both TAP and amiloride caused modest natriuresis and a marked reduction in potassium excretion. Amiloride is approximately 1000 times more potent than TAP when compared on the basis of drug concentration in the urine. The concentrations of both substances in urine (at effective doses) correspond to concentrations reported to be effective against sodium transport in amphibian membranes. The urinary concentrations of TAP also correspond to the concentrations required to inhibit paracellular cation movement in the gallbladder. Amiloride at the level tested (10(-3) M) did not seem to influence the paracellular pathway. The results neither establish nor disprove a role of the paracellular pathway in potassium secretion. Both TAP and amiloride are secreted by the renal tubules.
据报道，2,4,6-三氨基嘧啶（TAP）是几种上皮细胞阳离子特异性细胞旁传导途径的阻滞剂。该化合物还已知可抑制蛙皮中的钠转运。在麻醉大鼠的清除实验和离体灌注大鼠肾脏中研究了其对肾功能的影响，并与氨氯吡咪的作用进行了比较。还评估了这两种化合物对蛙胆囊电阻的影响。TAP和氨氯吡咪均引起适度的利钠作用，并显著降低钾排泄。以尿中药物浓度为基础进行比较时，氨氯吡咪的效力比TAP高约1000倍。两种物质在尿中的浓度（有效剂量时）与据报道对两栖动物膜中的钠转运有效的浓度相对应。TAP的尿浓度也与抑制胆囊细胞旁阳离子运动所需的浓度相对应。所测试水平（10⁻³ M）的氨氯吡咪似乎不影响细胞旁途径。这些结果既未证实也未否定细胞旁途径在钾分泌中的作用。TAP和氨氯吡咪均由肾小管分泌。
