Importance of the kidney in the correction of chloride-depletion alkalosis in the rat.

Correction of chloride-depletion alkalosis (CDA) may involve renal as well as extrarenal mechanisms. To determine the relative contribution of these mechanisms in a rat model of CDA produced by peritoneal dialysis (PD), we studied six groups of anesthetized Sprague-Dawley rats after PD. Groups II-IV and IIa were subjected to functional bilateral nephrectomy, and groups I and Ia were sham-operated. Groups I, Ia, II, and IIa were infused with isotonic fluid containing 70 mM Cl- and 40 mM HCO3-; the infusate in group III was 140 mM Cl- and in group IV, 70 mM neutral PO4 was substituted for Cl-. Groups I and Ia were infused at 0.5 ml . h-1 X 100 g body wt-1 and groups II, IIa, III, and IV at 0.25 ml . h-1 X 100 g-1. After 3 h of infusion, early partial correction with reciprocal changes in plasma Cl (+6.1 +/- 1.9 mmHg) and total CO2 (-6.0 +/- 0.8 meq/liter) occurred (P less than 0.01) only in group I. Hypokalemia (3.1 +/- 0.1 meq/liter) also occurred only in group I. The responses of groups Ia and IIa studied at 5 h were similar to those of groups I and II. These data suggest that the kidney, and not extrarenal mechanisms, is primarily responsible for the correction of CDA during infusion of chloride.