@2 acidification of distal renal tubule 肾小管上皮细胞 H -pump H2CO3→H+ NH3 NH4 HCO 3 H20+CO2 K 泌Ⅳ与泌K+拮抗,与泌NH3协同, 与肾小管液流量正变② acidification of distal renal tubule H+ -pump NH+ 4 泌H+与泌K+拮抗，与泌NH3协同， 与肾小管液流量正变 肾小管上皮细胞 H2CO3 H+ NH3 HCO- 3 H2O+CO2 K+