The proposed studies are designed to define the alterations in tubular sodium, chloride and bicarbonate reabsorption that occur when the number of functioning nephrons is reduced. Using micropuncture and microanalytic techniques in the rat, we will determine the relative contributions of changes in proximal and distal reabsorption in maintaining sodium balance and extracellular fluid composition in this model of renal insufficiency. These studies will be carried out for the first time in animals in which the surgically induced plasma losses are replaced to maintain volume status and renal function at levels seen in awake animals. The relative roles of alterations in single nephron GFR, aldosterone, peritibular physical factors, and """"""""natriuretic hormone"""""""" in producing the alterations sodium transport will be systematically examined. With respect to tubular bicarbonate transport in the remnant kidney, experiments will be conducted to examine the role of changes in filtered load chronic acid-base disturbances, and parathyroid hormone in producing the observed changes in reabsorption. These studies should provide new insights into the nature of the adaptive response of the kidney to nephron loss.
| Maddox, D A; Gennari, F J (1986) Load dependence of proximal tubular bicarbonate reabsorption in chronic metabolic alkalosis in the rat. J Clin Invest 77:709-16 |
| Maddox, D A; Horn, J F; Famiano, F C et al. (1986) Load dependence of proximal tubular fluid and bicarbonate reabsorption in the remnant kidney of the Munich-Wistar rat. J Clin Invest 77:1639-49 |
| Maddox, D A; Gennari, F J (1985) Load dependence of HCO3 and H2O reabsorption in the early proximal tubule of the Munich-Wistar rat. Am J Physiol 248:F113-21 |
