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Estimation of Free Water Back Diffusion during Water Diuresis in Man Using Lithium Clearance and Furosemide Effect: Some Unresolved Questions

  • E. J. Dorhout Mees
  • W. H. Boer
  • H. A. Koomans
Chapter
Part of the Developments in Nephrology book series (DINE, volume 18)

Abstract

The only way to localize tubular action of diuretics in man is by clearance techniques. The clearance of solute-free water (CH2O) is used to estimate NaCl reabsorption in the Loop of Henle and distal tubule. It is however well known that maximal CH2O underestimates distal NaCl reabsorption because a substantial fraction of generated free water disappears by back diffusion (BD), even in the absence of ADH (1). Bartoli cs (2) have proposed to analyze tubular functions and BD using the effects of furosemide (F) based on the assumption that F: a) completely blocks NaCl reabsorption in the Loop of Henle, but not elsewhere, b) completely abolishes osmotic gradients in the medulla, and thus eliminates BD. Consequently, maximal urine flow during F measures distal delivery, and the fact that without F less urine is produced is due to BD. The proximal reabsorption (Rprox) can be calculated from distal delivery and filtration rate

Keywords

Proximal Tubule Distal Tubule Back Diffusion Maximal Urine Flow Lithium Clearance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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Copyright information

© Martinus Nijhoff Publishing, Boston 1987

Authors and Affiliations

  • E. J. Dorhout Mees
    • 1
  • W. H. Boer
    • 1
  • H. A. Koomans
    • 1
  1. 1.Dept. of Nephrology and HypertensionUniversity HospitalUtrechtThe Netherlands

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