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. 1974 Nov;243(1):45–61. doi: 10.1113/jphysiol.1974.sp010741

Relationship between glucose and sodium excretion in the new-born dog

Jeffrey T Baker, Leonard I Kleinman
PMCID: PMC1330688  PMID: 4449064

Abstract

1. The relationship between renal glucose and sodium excretion was studied in thirty-three new-born dogs aged 1-14 days and in ten adult dogs.

2. Glucose was infused into the animals at rates sufficient to produce an amount of filtered glucose at least 1·5 times the tubular transport of glucose (saturating glucose load). In both puppies and adults tubular glucose reabsorption at saturating glucose loads varied directly with the glomerular filtration rate (r = 0·54 and 0·73 respectively, P < 0·01 for both).

3. In the puppy, as the fraction of filtered sodium excreted (CNa/CIn) increased from 0·05 to 0·45, the ratio, renal tubular glucose transport divided by glomerular filtration rate at saturating glucose loads, (TG/GFR)m, decreased from 3·7 to 1·7 mg/ml. (r = -0·75, P < 0·01). In the adult CNa/CIn was below 0·08 in all experiments and (TG/GFR)m was within the 95% confidence limits predicted by regression analysis of the data from puppies. Although mean (TG/GFR)m was greater in the adult than in the puppy (P < 0·01), when puppies had CNa/CIn similar to that for adults, they had (TG/GFR)m values equivalent to that for the adult.

4. There was excellent correlation between glucose excretion and water excretion for both adult and new-born dogs (r = 0·93 and 0·87, respectively). However, for any glucose loss, water loss was greater in the puppy than in the adult (P < 0·01).

5. During the control period total sodium excretion (per gram kidney) and CNa/CIn were similar in the new-born and adult dog. However, during glucose loading, the puppies excreted more sodium and had a higher CNa/CIn than did the adult, although glucose excretion was greater in the adult than in the puppy (P < 0·01 for all comparisons).

6. Glomerular blood flow, as measured by radioactive microspheres, was redistributed towards inner cortical nephrons during glucose loading in the puppy. There was no such redistribution of glomerular blood flow in the adult.

7. Sodium reabsorption beyond the proximal tubule was blocked with ethacrynic acid and chlorothiazide. In the puppy, the increase of CNa/CIn following a glucose load was the same whether the glucose load followed control or distal blockade collections, suggesting that reductions of sodium reabsorption following a glucose load probably came from the proximal tubule. CNa/CIn during glucose loading plus distal blockade was significantly (P < 0·01) higher in the puppy (0·598) than in the adult (0·280), indicating that glucose diuresis produced a greater inhibition of proximal tubular sodium reabsorption in the new-born than in the adult dog.

These results support the hypothesis that the high sodium excretion rate during glucose diuresis in the new-born dogs appears to be due to the greater sensitivity of the neonatal proximal tubule to the osmotic effect of glucose. When presented with a glucose osmotic load the new-born dog diminishes net proximal sodium reabsorption more than does the adult and thus depresses tubular glucose reabsorption to a greater extent. The lower values of maximal glucose transport rates found in new-born animals may be related, therefore, to the higher fractional sodium excretion rates during glucose diuresis rather than to a diminished intrinsic glucose transport capacity in the new-born kidney.

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Selected References

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

  1. Baker J. T., Kleinman L. I. Glucose reabsorption in the newborn dog kidney. Proc Soc Exp Biol Med. 1973 Feb;142(2):716–719. doi: 10.3181/00379727-142-37100. [DOI] [PubMed] [Google Scholar]
  2. Barger A. C. Renal hemodynamic factors in congestive heart failure. Ann N Y Acad Sci. 1966 Nov 22;139(2):276–284. doi: 10.1111/j.1749-6632.1966.tb41202.x. [DOI] [PubMed] [Google Scholar]
  3. EARLEY L. E., ORLOFF J. THIAZIDE DIURETICS. Annu Rev Med. 1964;15:149–166. doi: 10.1146/annurev.me.15.020164.001053. [DOI] [PubMed] [Google Scholar]
  4. Earley L. E., Martino J. A., Friedler R. M. Factors affecting sodium reabsorption by the proximal tubule as determined during blockade of distal sodium reabsorption. J Clin Invest. 1966 Nov;45(11):1668–1684. doi: 10.1172/JCI105474. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Earley L. E., Martino J. A. Influence of sodium balance on the ability of diuretics to inhibit tubular reabsorption. A study of factors that influence renal tubular sodium reabsorption in man. Circulation. 1970 Aug;42(2):323–334. doi: 10.1161/01.cir.42.2.323. [DOI] [PubMed] [Google Scholar]
  6. Gussin R. Z., Cafruny E. J. Renal sites of action of ethacrynic acid. J Pharmacol Exp Ther. 1966 Jul;153(1):148–158. [PubMed] [Google Scholar]
  7. Horster M., Valtin H. ostnatal development of renal function: micropuncture and clearance studies in the dog. J Clin Invest. 1971 Apr;50(4):779–795. doi: 10.1172/JCI106549. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Kleinman L. I., Reuter J. H. Maturation of glomerular blood flow distribution in the new-born dog. J Physiol. 1973 Jan;228(1):91–103. doi: 10.1113/jphysiol.1973.sp010074. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Kleinman L. I., Reuter J. H. Renal response of the new-born dog to a saline load: the role of intrarenal blood flow distribution. J Physiol. 1974 Jun;239(2):225–236. doi: 10.1113/jphysiol.1974.sp010565. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Kurtzman N. A., White M. G., Rogers P. W., Flynn J. J., 3rd Relationship of sodium reabsorption and glomerular filtration rate to renal glucose reabsorption. J Clin Invest. 1972 Jan;51(1):127–133. doi: 10.1172/JCI106782. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Schultze R. G., Berger H. The influence of GFR and saline expansion on TmG of the dog kidney. Kidney Int. 1973 May;3(5):291–297. doi: 10.1038/ki.1973.47. [DOI] [PubMed] [Google Scholar]
  12. TUDVAD F., VESTERDAL J. The maximal tubular transfer of glucose and para-amino hippurate in premature infants. Acta Paediatr. 1953 Jul;42(4):337–345. doi: 10.1111/j.1651-2227.1953.tb05601.x. [DOI] [PubMed] [Google Scholar]

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