On the mechanism of diminished urinary carbon dioxide tension caused by amiloride

Hulter, Henry N.; Ilnicki, Leon P.; Licht, J. Hamilton; Sebastian, Anthony
January 1982
Kidney International;Jan1982, Vol. 21 Issue 1, p8
Academic Journal
On the mechanism of diminished urinary carbon dioxide tension caused by amiloride. We investigated under both in vivo and in vitro conditions the mechanism whereby amiloride administration, a model of distal renal tubular acidosis in dogs, decreases the urine-to-blood PCO2 gradient (U-B PCO2.) in alkaline urine. The results demonstrate that U-B PCO2 is reduced in amiloride-induced dogs as previously reported m rats. The reduction in U-B PCO2 could not be attributed to amiloride-induced reductions in urinary HCO3-, concentration since the reduction in U-B PCO2 was observed over the same range of urinary HCO3- concentrations (150 to 250 mEq per liter) as that achieved prior to amiloride administration. U-B PCO2 correlated positively and linearly with urinary HCO3- concentration both prior to (P < 0.001) and during amiloride infusion (P < 0.001). Amiloride administration significantly decreased the slope (∂[U-B PCO2]/<[HCO3-]u) of the regression line (P ∂ 0.005). The possibility that amiloride might lower urine PCO2 by catalyzing intraluminal dehydration of H2CO3 was excluded by demonstrating that amiloride does not possess carbonic anhydrase activity. The additional possibility that amiloride might facilitate dissipation of carbon dioxide gradients through diffusion (as reported for carbonic anhydrase) was excluded by in vitro studies of the effect of amiloride on carbon dioxide diffusion. These findings suggest that the U-B P PCO2 lowering effect of amiloride is not caused by alterations in urinary [HCO3- ], CO2 diffusibility, or alterations in the dehydration rate of H2CO3 thereby providing strong support for the interpretation that reductions in U-B PCO2; during amiloride administration represent an impairment in distal nephron hydrogen ion secretion.


Related Articles

  • Factors influencing the formation of urinary carbon dioxide tension. Arruda, Jose A. I.; Nascimento, Luiz; Kumar, Surinder K.; Kurtzman, Neil A. // Kidney International;May1977, Vol. 11 Issue 5, p307 

    The factors controlling the formation of urinary carbon dioxide tension (Pco2) during sodium bicarbonate administration were studied in dogs. In highly alkaline urine (pH > 7.8), urine-blood (U-B) Pco2 rose in both normal and thyroparathyroidectomized (TPTX) dogs despite a significant difference...

  • The Metabolic and Respiratory Acidosis of Acute Pulmonary Edema. Aberman, Arnold; Fulop, Milford // Annals of Internal Medicine;Feb72, Vol. 76 Issue 2, p173 

    Examines consecutive cases of pulmonary edema due to left ventricular failure. Methodology used in the study; Factors affecting arterial carbon dioxide tension; Information on the presence of metabolic acidosis among patients.

  • Secondary hypocapnia fails to protect "whole body" intracellular pH during chronic HCl-acidosis in the dog. Clark, David D.; Chang, Bruce S.; Garella, Serafino G.; Cohen, Jordan J.; Madias, Nicolaos E. // Kidney International;Feb1983, Vol. 23 Issue 2, p336 

    Studies have demonstrated that the protective effect of secondary hypocapnia on plasma acidity during chronic HCl-acidosis is undermined by a renal-mediated decrement in plasma bicarbonate concentration induced by the hypocapnia itself. The present study was designed to assess whether the...

  • Comparison of arterial and venous pH, bicarbonate, Pco2 and Pa2 in initial emergency department assessment. Malatesha, G.; Singh, Nishith K.; Bharija, Ankur; Rehani, Bhavya; Goel, Ashish // Emergency Medicine Journal;Aug2007, Vol. 24 Issue 8, p569 

    The article discusses a study which examined whether venous blood gas (VBG) analysis is a reliable substitute for arterial blood gas (ABG) analysis in initial emergency department evaluation. The study compared the arterial and venous values of pH, bicarbonate, partial pressure of carbon dioxide...

  • Short-term regulation of acid-base homeostasis of body fluids. Clancy, John; McVicar, Andrew // British Journal of Nursing;9/13/2007, Vol. 16 Issue 16, p1016 

    The first in this two-part article explores the short-term homeostatic mechanisms involved in maintaining the 'acid-base balance' of body fluids. The second article identifies the intermediate and long-term homeostatic mechanisms involved in maintaining the 'acid-base balance'. The acid-base...

  • Deal with this dairy 'devil'. CARSON, VICKY // Southern Farmer (1541-2008);Dec2012, Vol. 11 Issue 12, p38 

    The article offers information on subacute ruminal acidosis (SARA) in dairy cows which is defined as a hydrogen-ion concentration (pH) of 5.8.

  • Molecular propeties of amiloride action and of its Na+ transporting targets. Frelin, Christian; Vigne, Paul; Barbry, Pascal; Lazdunski, Michel // Kidney International;Dec1987, Vol. 32 Issue 6, p785 

    Discusses the molecular properties of amiloride action and its extrarenal effects in relation to the cardiovascular system. Mechanistic properties of the renal Na+/H+ exchange system; Structural formula for amiloride and .selected amiloride derivatives; Presence of different isotypes of the...

  • Cathepsin B is more active at acidic pH and regulates airway surface liquid through the cleavage of γENaC. Tan, C.; Sameni, M.; Dang, Y.; He, H.; Sloane, B. F.; Stutts, J.; Tarran, R. // Proceedings of the Physiological Society;2013, p689P 

    BACKGROUND: Na+ transport via the amiloride-sensitive epithelial Na+ channel (ENaC) regulates airway surface liquid (ASL) volume and mucus clearance. In cystic fibrosis (CF) airways, increased sodium absorption depletes the ASL resulting in dysfunctional mucocilliary clearance and bacteria...

  • Carbon dioxide can also be a killer.  // PHC Profit Report;09/01/96, Vol. 4 Issue 17, p6 

    Presents advice from the US Labor Department on minimizing carbon dioxide poisoning. Hazards of carbon monoxide fumes from household water and space heating equipment; Importance of proper ventilation; Establishment of a procedure to inspect and maintain components that are part of carbon...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics