The Collection and Analysis of Fluid From Single Nephrons of the Mammalian Kidney

Walker, Arthur M.; Bott, P. A.; Oliver, Jean; MacDowell, Muriel

doi:10.1152/ajplegacy.1941.134.3.580

Cited by 371 publications

(116 citation statements)

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“…per kilo) in the normal animal (15) presumably because 85 to 90 per cent of the filtered water is reabsorbed in the proximal portions of the nephron (17)(18)(19). The fact that the creatinine or inulin U/P ratio during maximal water diuresis does not fall below this same range in diabetes insipidus (Fig.…”

Section: Mechanism Of Water Reabsorption During Dehydration--there Amentioning

confidence: 97%

“…The complete reabsorption of electrolyte, particularly of sodium, high in the proximal segment (19) would be the first essential for this operation. A reduced filtration rate would facilitate this process as well as the early attainment of osmotic equilibrium between tubular contents and renal interstitial fluid through the passive reabsorption of water.…”

Section: Effect Of Saline Ingestion On the Magnitude Of Polyuria--thmentioning

confidence: 99%

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The Control of the Renal Excretion of Water

Shannon

1942

Journal of Experimental Medicine

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Chronic polyuria following ablation of the neurohypophysis in the mammal is presumably due to a lack of adequate amounts of the posterior pituitary antidiuretic hormone. The polyuria of this condition has itself received considerable attention. What has not been commonly appreciated is the wide fluctuations to which it is subject and which are commonly the result of variables known to influence the water excretion of normal animals. The present investigations examine into the circumstances which surround the effect of variations in bodily hydration on the rate of water excretion in diabetes insipidus. The variations in hydration were produced by the administration and withdrawal of water and by the ingestion of saline solution. The experiments were designed to satisfy two ends. The first of these was a functional description of the potentialities of the nephron to reabsorb water in the absence of the antidiuretic hormone. The second was the clarification of the relationships among the individual processes within the nephron which together determine the renal excretion of water.EXPER rM-E.NTAL ~aterial.--Four female dogs with permanent diabetes insipidus were used. They were prepared for us by Dr. Allen Keller of the University of Alabama and were maintained in his laboratory for at least one year after the operation. The animals were fed a synthetic diet I during their stay in this laboratory permitting easy control of the foodstuff mixture, its caloric value, and the salt content. The caloric intake

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Section: Mechanism Of Water Reabsorption During Dehydration--there Amentioning

confidence: 97%

Section: Effect Of Saline Ingestion On the Magnitude Of Polyuria--thmentioning

confidence: 99%

The Control of the Renal Excretion of Water

Shannon

1942

Journal of Experimental Medicine

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“…In the mammalian kidney, 80 per cent of the fluid filtered in the glomerulus is absorbed by the proximal tubules. It was shown many years ago by Walker, Richards, and colleagues, for the amphibian (1) and mammalian kidneys (2), that under normal conditions, the fluid absorbed by the proximal tubule was isosmotic to the plasma, and that it was essentially of the same composition as the glomerular filtrate. Two possibilities were then considered to explain the mechanism of the absorption in the proximal tubule: (a) the primary step is an absorption of solutes, with water following passively, or (b) the colloid osmotic pressure exerted by the proteins circulating in the peritubular capillaries is sufficient to produce direct water absorption, the solutes following.…”

mentioning

confidence: 99%

Ion and Water Transport in the Proximal Tubules of the Kidney of Necturus maculosus

Whittembury

1960

The Journal of General Physiology

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The nature of the transport of ions and water in the proximal tubule of the kidney has been a subject of extraordinary interest for a long time. In the mammalian kidney, 80 per cent of the fluid filtered in the glomerulus is absorbed by the proximal tubules. It was shown many years ago by Walker, Richards, and colleagues, for the amphibian (1) and mammalian kidneys (2), that under normal conditions, the fluid absorbed by the proximal tubule was isosmotic to the plasma, and that it was essentially of the same composition as the glomerular filtrate. Two possibilities were then considered to explain the mechanism of the absorption in the proximal tubule: (a) the primary step is an absorption of solutes, with water following passively, or (b) the colloid osmotic pressure exerted by the proteins circulating in the peritubular capillaries is sufficient to produce direct water absorption, the solutes following.Wesson and Anslow (3) in experiments in dogs showed that in osmotic diuresis, Na and G1 were both absorbed against a chemical gradient and suggested the active nature of the Na transport; however, their conclusion was based on the assumption of a negligible effect of the distal tubule under their experimental conditions. That assumption has been subjected to criticism. They also did not consider electrical potential gradients.The concepts of active transport have evolved from early suggestions of dependence of transport on metabolism. This, however, is not a sufficient definition. Two generally acceptable definitions of an active transport process will be considered. Rosenberg (4) has defined as active transport any transport which takes place against an electrochemical potential gradient. Ussing (5) has defined active transport as movement of a substance that cannot be explained by simple diffusion. This definition is more general than the one given by Rosenberg, but is difficult to apply in practice for it requires a knowledge of the rate at which the substance in question crosses the membrane by simple diffusion. Equation 1 (5) describes the flux of an ion moving independently across a membrane, in the absence of temperature gradient, Rockefeller Foundation Fellow; on a leave of absence from Facultad de Medicina, Lima, Peru.

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“…Several hypotheses have evolved from the experiments of earlier workers (4,5) regarding the mechanism of proteinuria. The two hypotheses most often considered are:…”

mentioning

confidence: 99%