Effect of acute unilateral renal denervation on tubular sodium reabsorption in the dog.

The effects of acute denervation of the kidney on renal tubular sodium and water excretion were studied in anesthetized, hypophysectomized, and cortisone-treated mongrel dogs during stable water diuresis produced by the infusion of 2.5% dextrose. In all experiments, denervation natriuresis, and diuresis were observed without significant change in glomerular filtration rate (GRF) and renal plasma flow (RPF). Fractional sodium delivery to the distal nephron (CNa + CH2O/100 ml GFR) and fractional free water clearance (CH23/100 ml GFR) was significantly greater in the denervated kidney compared with the innervated kidney (9.6+/-1.2 vs. 6.7+/-0.9% and 8.8+/-1.2 vs. 6.5+/-0.8%, respectively). Distal tubular sodium reabsorption (CH2O/(CNa + CH2O)) was not significantly different. We conclude that renal denervation primarily affects the proximal tubule as manifested by a decrease in the reabsorption of sodium and water. A small effect of denervation on the distal nephron is not completely ruled out.