Borghetti A, Guariglia A, Minari M, Borghi L, Curti A, Montanari A, Novarini A
Proc Eur Dial Transplant Assoc. 1978;15:491-9.
The role of nephron loss, extracellular fluid volume (ECFV) expansion and body potassium stores on bicarbonate reabsorption in chronic renal failure (CRF) was evaluated. In 17 CRF and 3 control subjects, tubular HCO3 reabsorption was studied by HCO3 1M titration technique; ECFV (22Na space at 4th hour) and cell K content (muscle biopsy) were also determined. Nephron loss per se does not cause any change of HCO3 reabsorption rate per unit GFR. With ECFV expansion induced by HCO3 infusion, a Tm HCO3 is rapidly reached only in controls and in CRF patients showing a significant basal ECFV expansion. In these subjects reabsorbed HCO3/Na ratio is constant, suggesting that under these conditions, HCO3 reabsorption depends on the same mechanisms that control Na reabsorption. In cell K depleted CRF patients, HCO3 reabsorption rises more than in controls and no Tm HCO3 is detected, at least within the limits of isotonic ECFV expansion induced by titration; in these subjects HCO3 reabsorption does not appear to be limited by natriuretic factors. In CRF subjects with normal ECFV and cell K, there is a greater HCO3 tolerance to ECFV expansion induced by titration technique than in controls.
评估了肾单位丧失、细胞外液量（ECFV）扩张和机体钾储备对慢性肾衰竭（CRF）中碳酸氢盐重吸收的作用。对17例CRF患者和3例对照者，采用碳酸氢盐1M滴定技术研究肾小管HCO₃重吸收；同时测定ECFV（第4小时的²²Na空间）和细胞内钾含量（肌肉活检）。肾单位丧失本身不会导致单位肾小球滤过率（GFR）的HCO₃重吸收率发生任何变化。通过输注碳酸氢盐诱导ECFV扩张时，仅在对照组以及基础ECFV有显著扩张的CRF患者中能迅速达到HCO₃重吸收的Tm值。在这些受试者中，重吸收的HCO₃/Na比值恒定，这表明在这些情况下，HCO₃重吸收依赖于控制Na重吸收的相同机制。在细胞内钾缺乏的CRF患者中，HCO₃重吸收的增加幅度大于对照组，并且至少在滴定诱导的等渗ECFV扩张范围内未检测到HCO₃重吸收的Tm值；在这些受试者中，HCO₃重吸收似乎不受利钠因子的限制。在ECFV和细胞内钾正常的CRF受试者中，与对照组相比，对滴定技术诱导的ECFV扩张具有更高的HCO₃耐受性。
