Isolation of rat kidney cortical tubules enriched in proximal and distal segments

Scholer, D; Edelman, Isidore S.

doi:10.1152/ajprenal.1979.237.5.f350

Cited by 20 publications

(19 citation statements)

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“…At these extremes of sodium intake, intravascular volume was expanded and cardiac index increased, factors serving to further suppress proximal tubular reabsorption of sodium, thus theoretically en hancing both sodium and calcium excretion [17,43,[55][56][57], This speculation, combined with the documented increase in the filtered load of calcium, suggests that both absolute and fractional delivery of calcium out of the proximal tubule increased substantially. An even greater reliance on PTH-activated, distal nephron sites [58][59][60] to provide sufficient capacity for the reabsorption of the calcium would be anticipated. Our data indicate that this was not the case, as serum PTH concentrations and uri nary cAMP excretion actually declined with sodium load ing.…”

Section: Discussionmentioning

confidence: 99%

Urinary Calcium Excretion at Extremes of Sodium Intake in Normal Man

et al. 1981

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To elucidate the relationship between the renal regulation of sodium and calcium excretion at extremes of sodium intake, we studied 6 normal men ingesting a fixed, 400 mg/day calcium intake and four levels of sodium intake from 10 to 1,500 mEq/day. Serum ionized calcium was not influenced by sodium intake. Blood pressure and cardiac index increased modestly. Urinary calcium excretion increased to 262 ± 53 mg/day (mean ± SE). Plasma norepinephrine concentration, serum PTH levels, hematocrit, total serum protein concentrations and CO₂ content decreased with increasing sodium intake. Urinary cAMP increased as sodium intake was raised from 10 to 300 mEq/day, but subsequently decreased to basal values. Urinary calcium and sodium excretion were related (p < 0.001) in a nonlinear fashion as were the fractional excretions of these cations (p < 0.001). The filtered calcium load and the fractional calcium excretion were directly and linearly related (p < 0.001). We conclude that the effect of sodium intake on urinary calcium excretion principally reflects changes in the filtered calcium load rather than changes in renal sodium handling. Calcium homeostasis at extremes of sodium intake does not appear to be critically dependent upon PTH-mediated mechanisms. The data suggest that the proximal tubule has a remarkable capacity to dissociate calcium resorption from that of sodium.

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Section: Discussionmentioning

confidence: 99%

Urinary Calcium Excretion at Extremes of Sodium Intake in Normal Man

et al. 1981

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“…The feasibility of fractionating useful amounts of nephron components for biochemical studies by density gradient centrifugation (using Ficoll) has already been demonstrated by Scholer & Edelman (1979); and the problem of fibroblastic overgrowth can be overcome either by initiating cultures with only epithelial cells (Horster, 1980) or by the use of selective media favouring epithelial proliferation (Taub & Sato, 1980;Taub, Chuman, Saier & Sato, 1979;Gilbert & Migeon, 1975, 1977.…”

Section: Introductionmentioning

confidence: 99%

Isolation and Culture of Renal Cortical Tubules From Neonate Rabbit Kidneys

1982

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SUMMARYA method is described for the preparation of an enriched population of proximal tubules from the cortices of neonate (21-28 d old) rabbits. The method uses collagenase-hyaluronidase digestion, followed by gentle shear to yield a suspension of tubules and glomeruli. Tubular enrichment is achieved by discontinuous density gradient centrifugation in a Percoll gradient. Two fractions were obtained by this method. The denser fraction contained predominantly proximal tubules, was depleted of glomeruli and was enriched in the proximal tubule marker enzyme alkaline phosphatase. Qualitatively similar results to those obtained with neonate animals were obtained with adult tissue. Neonate tubules from the denser gradient fraction grew readily in tissue culture. When examined by electron microscopy the cells exhibited a marked polarity of ultrastructural organization and retained apical tight junctions. Despite this, there was an obvious loss of structure in comparison with in vivo proximal tubule cells. The use of primary culture techniques to study in vitro renal epithelial function is discussed.

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“…Tubule suspensions were prepared following a mo~fication of the methods of Scholer and Edelman [6] and Vinay et al [7]. In brief, healthy male Sprague-Dawley rats (3 months old) were anesthetized with diethyl ether and killed by cervical dislocation.…”

Section: Methodsmentioning

confidence: 99%

Ouabain‐insensitive, Na‐ATPase activity in pure suspensions of rat kidney proximal tubules

et al. 1990

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The present work was undertaken to evaluate the dist~bution of the Na-ATPase activity in the different components of the rat kidney cortex. Suspensions of glomeruli, proximal and distal tubules were prepared following a collagenase digestion of outermost kidney cortex slices and a separation on a Percoll gradient. It was found that the Na-ATPase activity is higher in the fraction enriched in proximal tubules. The fraction enriched in glomeruli and in distal tubules show also a Na-ATPase activity, but it is lower.

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Isolation of rat kidney cortical tubules enriched in proximal and distal segments

Cited by 20 publications

References 0 publications

Urinary Calcium Excretion at Extremes of Sodium Intake in Normal Man

Urinary Calcium Excretion at Extremes of Sodium Intake in Normal Man

Isolation and Culture of Renal Cortical Tubules From Neonate Rabbit Kidneys

Ouabain‐insensitive, Na‐ATPase activity in pure suspensions of rat kidney proximal tubules

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