We studied two groups of rats acutely loaded with bicarbonate, control rats on a standard diet and rats kept on a K-free diet for 3 wk. Compared with controls, K-depleted rats had reduced fractional excretion of bicarbonate despite their elevated filtered bicarbonate load. Distal bicarbonate reabsorption increased in K-depleted rats. In the presence of almost identical early distal bicarbonate loads (481±40 pmol/min in controls and 444±50 pmol/min in K depletion), distal bicarbonate reabsorption was significantly enhanced in K depletion (247±17 pmol/min) as compared with controls (179±18 pmol/min). These values are significantly different from each other, and both are severalfold higher than bicarbonate reabsorption in nonloaded conditions. In conclusion, (a) distal bicarbonate reabsorption is load dependent, and (b) distal bicarbonate reabsorption is stimulated in K depletion.
Renal bicarbonate reabsorption in the rat. II Distal tubule load dependence and effect of hypokalemia
CAPASSO, Giovambattista;
1987
Abstract
We studied two groups of rats acutely loaded with bicarbonate, control rats on a standard diet and rats kept on a K-free diet for 3 wk. Compared with controls, K-depleted rats had reduced fractional excretion of bicarbonate despite their elevated filtered bicarbonate load. Distal bicarbonate reabsorption increased in K-depleted rats. In the presence of almost identical early distal bicarbonate loads (481±40 pmol/min in controls and 444±50 pmol/min in K depletion), distal bicarbonate reabsorption was significantly enhanced in K depletion (247±17 pmol/min) as compared with controls (179±18 pmol/min). These values are significantly different from each other, and both are severalfold higher than bicarbonate reabsorption in nonloaded conditions. In conclusion, (a) distal bicarbonate reabsorption is load dependent, and (b) distal bicarbonate reabsorption is stimulated in K depletion.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.