Sabolić I, Brown D, Gluck S L, Alper S L
Institute for Medical Research and Occupational Health, Zagreb, Croatia.
Kidney Int. 1997 Jan;51(1):125-37. doi: 10.1038/ki.1997.16.
The cortical collecting duct (CCD) mediates net secretion or reabsorption of protons according to systemic acid/base status. Using indirect immunofluorescence, we examined the localization and abundance of the vacuolar H(+)-ATPase and the AE1 anion exchanger in intercalated cells (IC) of rat kidney connecting segment (CNT) and CCD during acute (6 hr) metabolic (NH4Cl) acidosis and respiratory (NaHCO3) alkalosis. AE1 immunostaining intensity quantified by confocal microscopy was elevated in metabolic acidosis and substantially reduced in metabolic alkalosis. AE1 immunostaining was restricted to Type A IC in all conditions, and the fraction of AE1+IC was unchanged in CNT and CCd. Metabolic acidosis was accompanied by redistribution of H(+)-ATPase immunostaining towards the apical surface of IC, and metabolic alkalosis was accompanied by H(+)-ATPase redistribution towards the basal surface of IC. Therefore, acute metabolic acidosis produced changes consistent with increased activity of Type A IC and decreased activity of Type B IC, whereas acute metabolic alkalosis produced changes corresponding to increased activity of Type B IC and decreased activity of Type A IC. These data demonstrate that acute systemic acidosis and alkalosis modulate the cellular distribution of two key transporters involved in proton secretion in the distal nephron.
皮质集合管（CCD）根据全身酸碱状态介导质子的净分泌或重吸收。我们利用间接免疫荧光法，研究了大鼠肾连接段（CNT）和CCD闰细胞（IC）中液泡H(+)-ATP酶和AE1阴离子交换体在急性（6小时）代谢性（氯化铵）酸中毒和呼吸性（碳酸氢钠）碱中毒期间的定位和丰度。通过共聚焦显微镜定量的AE1免疫染色强度在代谢性酸中毒时升高，在代谢性碱中毒时显著降低。在所有情况下，AE1免疫染色都局限于A型闰细胞，并且在CNT和CCD中AE1阳性闰细胞的比例没有变化。代谢性酸中毒伴随着H(+)-ATP酶免疫染色向闰细胞顶端表面的重新分布，而代谢性碱中毒伴随着H(+)-ATP酶向闰细胞基底表面的重新分布。因此，急性代谢性酸中毒产生的变化与A型闰细胞活性增加和B型闰细胞活性降低一致，而急性代谢性碱中毒产生的变化与B型闰细胞活性增加和A型闰细胞活性降低相对应。这些数据表明，急性全身酸中毒和碱中毒可调节远端肾单位中参与质子分泌的两种关键转运体的细胞分布。
