Renal reabsorption of phosphate during development

tubular events

Frederick J. Kaskel, Adarsh M. Kumar, Leonard G. Feld, Adrian Spitzer

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Studies performed in our laboratory on the isolated perfused kidney of the guinea pig have demonstrated that the rate of Pi reabsorption is substantially greater in the newborn than in the adult, when appropriate corrections are being made either for differences in glomerular filtration rate (GFR) or in renal tubular mass. In order to determine the location of this enhanced reabsorption along the nephron, micropuncture experiments were performed on euvolemic, non-fasted guinea pigs 5-14 and 42-49 days of age, maintained on standard guinea-pig chow diet (0.76% Pi). Concomitant measurements of overall kidney function were also obtained. The results confirmed that fractional reabsorption of Pi (TRPi%) across the entire kidney was significantly higher (P<0.01) in the newborn (89.93±2.55%) than in the adult (78.25±2.89%) animals. The difference was also significant (P<0.05) when TRPi was expressed in mol/ml GFR (1.87±0.14 vs 1.53±0.12, respectively). At comparable locations along the proximal tubule (TF/Pin of 1.90±0.16 in the newborn, and 1.79±0.15 in the adult, P>0.70), the fraction of the filtered load of Pi reabsorbed was significantly higher (P<0.001) in the immature (76.66±2.74%) than in the mature (67.21±2.74%) guinea pigs. Estimates based on the differences between proximal Pi reabsorption and the urinary excretion of Pi indicate that the reabsorption of Pi in tubular segments located beyond the proximal tubule is also enhanced in the newborn when compared with the adult (15.62±2.11% vs 10.51±1.83%, respectively, P<0.05). Alternatively, this finding may be interpreted to represent a higher fractional reabsorption of Pi by deep nephrons.

Original languageEnglish (US)
Pages (from-to)129-134
Number of pages6
JournalPediatric Nephrology
Volume2
Issue number1
DOIs
StatePublished - Mar 1988

Fingerprint

Guinea Pigs
Phosphates
Kidney
Nephrons
Glomerular Filtration Rate
Punctures
Diet
Renal Reabsorption

Keywords

  • Development
  • Guinea pig
  • Phosphate
  • Proximal tubule

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Nephrology

Cite this

Renal reabsorption of phosphate during development : tubular events. / Kaskel, Frederick J.; Kumar, Adarsh M.; Feld, Leonard G.; Spitzer, Adrian.

In: Pediatric Nephrology, Vol. 2, No. 1, 03.1988, p. 129-134.

Research output: Contribution to journalArticle

Kaskel, Frederick J. ; Kumar, Adarsh M. ; Feld, Leonard G. ; Spitzer, Adrian. / Renal reabsorption of phosphate during development : tubular events. In: Pediatric Nephrology. 1988 ; Vol. 2, No. 1. pp. 129-134.
@article{a7416c314e7b43d0be03a0d697f2e396,
title = "Renal reabsorption of phosphate during development: tubular events",
abstract = "Studies performed in our laboratory on the isolated perfused kidney of the guinea pig have demonstrated that the rate of Pi reabsorption is substantially greater in the newborn than in the adult, when appropriate corrections are being made either for differences in glomerular filtration rate (GFR) or in renal tubular mass. In order to determine the location of this enhanced reabsorption along the nephron, micropuncture experiments were performed on euvolemic, non-fasted guinea pigs 5-14 and 42-49 days of age, maintained on standard guinea-pig chow diet (0.76{\%} Pi). Concomitant measurements of overall kidney function were also obtained. The results confirmed that fractional reabsorption of Pi (TRPi{\%}) across the entire kidney was significantly higher (P<0.01) in the newborn (89.93±2.55{\%}) than in the adult (78.25±2.89{\%}) animals. The difference was also significant (P<0.05) when TRPi was expressed in mol/ml GFR (1.87±0.14 vs 1.53±0.12, respectively). At comparable locations along the proximal tubule (TF/Pin of 1.90±0.16 in the newborn, and 1.79±0.15 in the adult, P>0.70), the fraction of the filtered load of Pi reabsorbed was significantly higher (P<0.001) in the immature (76.66±2.74{\%}) than in the mature (67.21±2.74{\%}) guinea pigs. Estimates based on the differences between proximal Pi reabsorption and the urinary excretion of Pi indicate that the reabsorption of Pi in tubular segments located beyond the proximal tubule is also enhanced in the newborn when compared with the adult (15.62±2.11{\%} vs 10.51±1.83{\%}, respectively, P<0.05). Alternatively, this finding may be interpreted to represent a higher fractional reabsorption of Pi by deep nephrons.",
keywords = "Development, Guinea pig, Phosphate, Proximal tubule",
author = "Kaskel, {Frederick J.} and Kumar, {Adarsh M.} and Feld, {Leonard G.} and Adrian Spitzer",
year = "1988",
month = "3",
doi = "10.1007/BF00870393",
language = "English (US)",
volume = "2",
pages = "129--134",
journal = "Pediatric Nephrology",
issn = "0931-041X",
publisher = "Springer Verlag",
number = "1",

}

TY - JOUR

T1 - Renal reabsorption of phosphate during development

T2 - tubular events

AU - Kaskel, Frederick J.

AU - Kumar, Adarsh M.

AU - Feld, Leonard G.

AU - Spitzer, Adrian

PY - 1988/3

Y1 - 1988/3

N2 - Studies performed in our laboratory on the isolated perfused kidney of the guinea pig have demonstrated that the rate of Pi reabsorption is substantially greater in the newborn than in the adult, when appropriate corrections are being made either for differences in glomerular filtration rate (GFR) or in renal tubular mass. In order to determine the location of this enhanced reabsorption along the nephron, micropuncture experiments were performed on euvolemic, non-fasted guinea pigs 5-14 and 42-49 days of age, maintained on standard guinea-pig chow diet (0.76% Pi). Concomitant measurements of overall kidney function were also obtained. The results confirmed that fractional reabsorption of Pi (TRPi%) across the entire kidney was significantly higher (P<0.01) in the newborn (89.93±2.55%) than in the adult (78.25±2.89%) animals. The difference was also significant (P<0.05) when TRPi was expressed in mol/ml GFR (1.87±0.14 vs 1.53±0.12, respectively). At comparable locations along the proximal tubule (TF/Pin of 1.90±0.16 in the newborn, and 1.79±0.15 in the adult, P>0.70), the fraction of the filtered load of Pi reabsorbed was significantly higher (P<0.001) in the immature (76.66±2.74%) than in the mature (67.21±2.74%) guinea pigs. Estimates based on the differences between proximal Pi reabsorption and the urinary excretion of Pi indicate that the reabsorption of Pi in tubular segments located beyond the proximal tubule is also enhanced in the newborn when compared with the adult (15.62±2.11% vs 10.51±1.83%, respectively, P<0.05). Alternatively, this finding may be interpreted to represent a higher fractional reabsorption of Pi by deep nephrons.

AB - Studies performed in our laboratory on the isolated perfused kidney of the guinea pig have demonstrated that the rate of Pi reabsorption is substantially greater in the newborn than in the adult, when appropriate corrections are being made either for differences in glomerular filtration rate (GFR) or in renal tubular mass. In order to determine the location of this enhanced reabsorption along the nephron, micropuncture experiments were performed on euvolemic, non-fasted guinea pigs 5-14 and 42-49 days of age, maintained on standard guinea-pig chow diet (0.76% Pi). Concomitant measurements of overall kidney function were also obtained. The results confirmed that fractional reabsorption of Pi (TRPi%) across the entire kidney was significantly higher (P<0.01) in the newborn (89.93±2.55%) than in the adult (78.25±2.89%) animals. The difference was also significant (P<0.05) when TRPi was expressed in mol/ml GFR (1.87±0.14 vs 1.53±0.12, respectively). At comparable locations along the proximal tubule (TF/Pin of 1.90±0.16 in the newborn, and 1.79±0.15 in the adult, P>0.70), the fraction of the filtered load of Pi reabsorbed was significantly higher (P<0.001) in the immature (76.66±2.74%) than in the mature (67.21±2.74%) guinea pigs. Estimates based on the differences between proximal Pi reabsorption and the urinary excretion of Pi indicate that the reabsorption of Pi in tubular segments located beyond the proximal tubule is also enhanced in the newborn when compared with the adult (15.62±2.11% vs 10.51±1.83%, respectively, P<0.05). Alternatively, this finding may be interpreted to represent a higher fractional reabsorption of Pi by deep nephrons.

KW - Development

KW - Guinea pig

KW - Phosphate

KW - Proximal tubule

UR - http://www.scopus.com/inward/record.url?scp=0023931745&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023931745&partnerID=8YFLogxK

U2 - 10.1007/BF00870393

DO - 10.1007/BF00870393

M3 - Article

VL - 2

SP - 129

EP - 134

JO - Pediatric Nephrology

JF - Pediatric Nephrology

SN - 0931-041X

IS - 1

ER -