Abstract
The present studies examined the effect of three-fourths nephrectomy on the rate of acidification, i.e., total CO2 (tCO2) absorption (JtCO2) in the superficial distal tubule of the rat. Total glomerular filtration rate following three-fourths nephrectomy was 1.29 ± 0.06 vs. 3.29 ± 0.08 ml/min in sham controls, P < 0.001. Systemic acid-base parameters were the same in both groups, but urine pH was lower in nephrectomized rats. In vivo microperfusion with identical isohydric solutions revealed that the JtCO2, fluid absorption (Jv), lumen-negative transepithelial potential difference (VT) were all significantly greater in the distal tubule of remnant kidneys. As the relative increase in Jv exceeded JtCO2, the perfusate tCO2 concentration increased markedly in remnant kidney distal tubules from 30.3 ± 0.59 to 39.9 ± 1.73 mM. To determine if the increase in tCO2 concentration accounted for the difference in JtCO2, a second control group was studied using a perfusate tCO2 concentration of 39.6 ± 0.79 mM. Distal tubular JtCO2, Jv, and VT were significantly less in this control group than in the remnant kidney group. In separate studies, 10-4 M amiloride was added to the perfusate used in remnant kidneys and controls studied with the elevated perfusate tCO2 concentration. The addition of 10-4 M amiloride to the perfusate reduced VT and JtCO2. At identical values for VT, JtCO2 was higher in the distal tubule of remnant kidneys than in controls. We conclude the following. 1) The rate of acidification is increased in the distal tubule of remnant kidneys. This increase in acidification presumably contributes to the maintenance of systemic acid-base balance in this experimental model. 2) The measured increase in distal tubular JtCO2 in the remnant kidney relative to controls in these studies was not dependent on a more favorable electrical gradient for proton secretion.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Renal Fluid and Electrolyte Physiology |
| Volume | 258 |
| Issue number | 1 27-1 |
| State | Published - 1990 |
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Keywords
- Acidification
- Distal nephron
- Remnant kidney
ASJC Scopus subject areas
- Physiology
Cite this
Distal tubular acidification in the remnant kidney. / Kunau, R. T.; Walker, K. A.
In: American Journal of Physiology - Renal Fluid and Electrolyte Physiology, Vol. 258, No. 1 27-1, 1990.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Distal tubular acidification in the remnant kidney
AU - Kunau, R. T.
AU - Walker, K. A.
PY - 1990
Y1 - 1990
N2 - The present studies examined the effect of three-fourths nephrectomy on the rate of acidification, i.e., total CO2 (tCO2) absorption (JtCO2) in the superficial distal tubule of the rat. Total glomerular filtration rate following three-fourths nephrectomy was 1.29 ± 0.06 vs. 3.29 ± 0.08 ml/min in sham controls, P < 0.001. Systemic acid-base parameters were the same in both groups, but urine pH was lower in nephrectomized rats. In vivo microperfusion with identical isohydric solutions revealed that the JtCO2, fluid absorption (Jv), lumen-negative transepithelial potential difference (VT) were all significantly greater in the distal tubule of remnant kidneys. As the relative increase in Jv exceeded JtCO2, the perfusate tCO2 concentration increased markedly in remnant kidney distal tubules from 30.3 ± 0.59 to 39.9 ± 1.73 mM. To determine if the increase in tCO2 concentration accounted for the difference in JtCO2, a second control group was studied using a perfusate tCO2 concentration of 39.6 ± 0.79 mM. Distal tubular JtCO2, Jv, and VT were significantly less in this control group than in the remnant kidney group. In separate studies, 10-4 M amiloride was added to the perfusate used in remnant kidneys and controls studied with the elevated perfusate tCO2 concentration. The addition of 10-4 M amiloride to the perfusate reduced VT and JtCO2. At identical values for VT, JtCO2 was higher in the distal tubule of remnant kidneys than in controls. We conclude the following. 1) The rate of acidification is increased in the distal tubule of remnant kidneys. This increase in acidification presumably contributes to the maintenance of systemic acid-base balance in this experimental model. 2) The measured increase in distal tubular JtCO2 in the remnant kidney relative to controls in these studies was not dependent on a more favorable electrical gradient for proton secretion.
AB - The present studies examined the effect of three-fourths nephrectomy on the rate of acidification, i.e., total CO2 (tCO2) absorption (JtCO2) in the superficial distal tubule of the rat. Total glomerular filtration rate following three-fourths nephrectomy was 1.29 ± 0.06 vs. 3.29 ± 0.08 ml/min in sham controls, P < 0.001. Systemic acid-base parameters were the same in both groups, but urine pH was lower in nephrectomized rats. In vivo microperfusion with identical isohydric solutions revealed that the JtCO2, fluid absorption (Jv), lumen-negative transepithelial potential difference (VT) were all significantly greater in the distal tubule of remnant kidneys. As the relative increase in Jv exceeded JtCO2, the perfusate tCO2 concentration increased markedly in remnant kidney distal tubules from 30.3 ± 0.59 to 39.9 ± 1.73 mM. To determine if the increase in tCO2 concentration accounted for the difference in JtCO2, a second control group was studied using a perfusate tCO2 concentration of 39.6 ± 0.79 mM. Distal tubular JtCO2, Jv, and VT were significantly less in this control group than in the remnant kidney group. In separate studies, 10-4 M amiloride was added to the perfusate used in remnant kidneys and controls studied with the elevated perfusate tCO2 concentration. The addition of 10-4 M amiloride to the perfusate reduced VT and JtCO2. At identical values for VT, JtCO2 was higher in the distal tubule of remnant kidneys than in controls. We conclude the following. 1) The rate of acidification is increased in the distal tubule of remnant kidneys. This increase in acidification presumably contributes to the maintenance of systemic acid-base balance in this experimental model. 2) The measured increase in distal tubular JtCO2 in the remnant kidney relative to controls in these studies was not dependent on a more favorable electrical gradient for proton secretion.
KW - Acidification
KW - Distal nephron
KW - Remnant kidney
UR - http://www.scopus.com/inward/record.url?scp=0025067426&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025067426&partnerID=8YFLogxK
M3 - Article
C2 - 2154127
AN - SCOPUS:0025067426
VL - 258
JO - American Journal of Physiology - Renal Physiology
JF - American Journal of Physiology - Renal Physiology
SN - 0363-6127
IS - 1 27-1
ER -