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. 1967 Jul;46(7):1178–1188. doi: 10.1172/JCI105611

Functional Characteristics of the Diluting Segment of the Dog Nephron and the Effect of Extracellular Volume Expansion on its Reabsorptive Capacity*

Garabed Eknoyan 1, Wadi N Suki 1, Floyd C Rector Jr 1, Donald W Seldin 1,†
PMCID: PMC297117  PMID: 6027081

Abstract

The functional characteristics of the ascending limb of Henle's loop were examined during hypotonic saline infusion by measuring solutefree water clearance (CH2O) at varying rates of solute delivery. The influence of expansion of extracellular volume was studied by comparing CH2O during hypotonic saline diuresis in normal dogs with dogs whose extracellular volume had been expanded acutely by saline infusions or chronically by the administration of deoxycorticosterone acetate and salt.

In normal animals hypotonic saline infusions greatly increased urine flow (V) and CH2O without appreciably augmenting osmolar clearance (Cosm). CH2O was, therefore, analyzed as a function of V, rather than Cosm, since V was the best estimate of delivery of filtrate to the diluting segment. CH2O increased as a linear function of V without any evidence of saturation.

The validity of interpreting increases in CH2O and V as indications of increased sodium reabsorption and delivery was reinforced by tissue studies that disclosed a rise in papillary osmolality with rising urine flows. The observed increase in CH2O and V could not, therefore, be due to a decrease in back diffusion of solute-free water as a result of a diminished osmotic driving force, but probably represented increased formation consequent to augmented delivery as a result of decreased fractional reabsorption in the proximal tubule.

In animals whose extracellular volume was acutely or chronically overexpanded before the infusion of hypotonic saline, sodium excretion was greater, and CH2O less, at any given V. Although the curve relating CH2O to V was flatter than in the control group, no tubular maximum was observed. The diminished CH2O in this group was interpreted to mean that massive expansion of extracellular volume inhibits sodium reabsorption in the ascending limb of Henle's loop.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ARNDT J. O. DIURESIS INDUCED BY WATER INFUSION INTO THE CAROTID LOOP AND ITS INHIBITION BY SMALL HEMORRHAGE. THE COMPETITION OF VOLUME- AND OSMOCONTROL. Pflugers Arch Gesamte Physiol Menschen Tiere. 1965 Jan 11;282:313–322. doi: 10.1007/BF00412506. [DOI] [PubMed] [Google Scholar]
  2. BLYTHE W. B., WELT L. G. DISSOCIATION BETWEEN FILTERED LOAD OF SODIUM AND ITS RATE OF EXCRETION IN THE URINE. J Clin Invest. 1963 Sep;42:1491–1496. doi: 10.1172/JCI104833. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. BRICKER N. S., KLAHR S., RIESELBACH R. E. THE FUNCTIONAL ADAPTATION OF THE DISEASED KIDNEY. I. GLOMERULAR FILTRATION RATE. J Clin Invest. 1964 Oct;43:1915–1921. doi: 10.1172/JCI105065. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. BUCHBORN E., EDEL H., ANASTASAKIS S. Zur Endokrinologie des distalen Nephrons. I. Klinische Differenzierung und Messung der Phasen I, II und III der Harnkonzentrierung. Klin Wochenschr. 1959 Apr 1;37(7):347–355. doi: 10.1007/BF01483484. [DOI] [PubMed] [Google Scholar]
  5. BURG M. B., PAPPER S., ROSENBAUM J. D. Factors influencing the diuretic response to ingested water. J Lab Clin Med. 1961 Apr;57:533–545. [PubMed] [Google Scholar]
  6. Clapp J. R., Robinson R. R. Osmolality of distal tubular fluid in the dog. J Clin Invest. 1966 Dec;45(12):1847–1853. doi: 10.1172/JCI105488. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. DIRKS J. H., CIRKSENA W. J., BERLINER R. W. THE EFFECTS OF SALINE INFUSION ON SODIUM REABSORPTION BY THE PROXIMAL TUBULE OF THE DOG. J Clin Invest. 1965 Jul;44:1160–1170. doi: 10.1172/JCI105223. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. EARLY L. E., FRIEDLER R. M. OBSERVATIONS ON THE MECHANISM OF DECREASED TUBULAR REABSORPTION OF SODIUM AND WATER DURING SALINE LOADING. J Clin Invest. 1964 Oct;43:1928–1937. doi: 10.1172/JCI105067. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. GOLDSMITH C., BEASLEY H. K., WHALLEY P. J., RECTOR F. C., Jr, SELDIN D. W. The effect of salt deprivation on the urinary concentrating mechanism in the dog. J Clin Invest. 1961 Nov;40:2043–2052. doi: 10.1172/JCI104430. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. GOLDSMITH C., RECTOR F. C., Jr, SELDIN D. W. Evidence for a direct effect of serum sodium concentration on sodium reabsorption. J Clin Invest. 1962 Apr;41:850–859. doi: 10.1172/JCI104542. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. GOODMAN B., COHEN J. A., LEVITT M. F., KAHN M. RENAL CONCENTRATION IN THE NORMAL DOG: EFFECT OF AN ACUTE REDUCTION IN SALT EXCRETION. Am J Physiol. 1964 May;206:1123–1130. doi: 10.1152/ajplegacy.1964.206.5.1123. [DOI] [PubMed] [Google Scholar]
  12. KAMM D. E., LEVINSKY N. G. INHIBITION OF RENAL TUBULAR SODIUM REABSORPTION BY HYPERNATREMIA. J Clin Invest. 1965 Jul;44:1144–1150. doi: 10.1172/JCI105221. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. KLEEMAN C. R., CUTLER R., MAXWELL M. H., BERNSTEIN L., DOWLING J. T. Effect of various diuretic agents on maximal sustained water diuresis. J Lab Clin Med. 1962 Aug;60:224–244. [PubMed] [Google Scholar]
  14. PILKINGTON L. A., BINDER R., DEHAAS J. C., PITTS R. F. INTRARENAL DISTRIBUTION OF BLOOD FLOW. Am J Physiol. 1965 Jun;208:1107–1113. doi: 10.1152/ajplegacy.1965.208.6.1107. [DOI] [PubMed] [Google Scholar]
  15. RECTOR F. C., Jr, VANGIESEN G., KIIL F., SELDIN D. W. INFLUENCE OF EXPANSION OF EXTRACELLULAR VOLUME ON TUBULAR REABSORPTION OF SODIUM INDEPENDENT OF CHANGES IN GLOMERULAR FILTRATION RATE AND ALDOSTERONE ACTIVITY. J Clin Invest. 1964 Mar;43:341–348. doi: 10.1172/JCI104919. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Smith H. W., Finkelstein N., Aliminosa L., Crawford B., Graber M. THE RENAL CLEARANCES OF SUBSTITUTED HIPPURIC ACID DERIVATIVES AND OTHER AROMATIC ACIDS IN DOG AND MAN. J Clin Invest. 1945 May;24(3):388–404. doi: 10.1172/JCI101618. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. VANGIESEN G., REESE M., KIIL F., RECTOR F. C., Jr, SELDIN D. W. THE CHARACTERISTICS OF RENAL HYPOPERFUSION IN DOGS WITH ACUTE AND CHRONIC REDUCTIONS IN GLOMERULAR FILTRATION RATE AS DISCLOSED BY THE PATTERN OF WATER AND SOLUTE EXCRETION AFTER HYPOTONIC SALINE INFUSIONS. J Clin Invest. 1964 Mar;43:416–424. doi: 10.1172/JCI104926. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. WALSER M., DAVIDSON D. G., ORLOFF J. The renal clearance of alkali-stable inulin. J Clin Invest. 1955 Oct;34(10):1520–1523. doi: 10.1172/JCI103204. [DOI] [PMC free article] [PubMed] [Google Scholar]

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