Effect of phosphorus restriction on renal response to oral and intravenous protein loads in rats

E. S. Kraus, L. Cheng, I. Sikorski, D. A. Spector

Research output: Contribution to journalArticle

Abstract

Dietary phosphorus restriction ameliorates renal injury in rats. This may be due to changes in renal hemodynamics, including those factors associated with protein-induced hyperfiltration. To test this, we measured inulin clearance (C(In)), p-aminohippuric acid clearance (C(PAH)), mean arterial blood pressure, and renal vascular resistance (RVR) 1 h before and 100 min after either oral gavage of 2 g bovine serum albumin or intravenous infusion of 5% glycine in female Sprague-Dawley rats previously fed for 3-8 wk a 0.5% or a 0.1% phosphorus diet. Baseline C(In), C(PAH), blood pressure, and RVR were similar. After albumin gavage, C(In) rose 20% (P < 0.01) for the 0.5% phosphorus group but did not change for rats fed the 0.1% phosphorus diet. Other measured parameters, including plasma glucagon and renin activity, were not influenced by dietary phosphorus content. In contrast, during intravenous infusion of glycine, hyperfiltration was induced in phosphorus-restricted rats. Thus dietary phosphorus restriction ablates oral protein but not intravenous amino acid-induced hyperfiltration, suggesting a gut-mediated mechanism for the former. These data highlight the potential importance of dietary phosphorus as a mediator of renal hemodynamics.

Original languageEnglish (US)
Pages (from-to)F752-F759
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume264
Issue number4 33-4
DOIs
StatePublished - 1993

Keywords

  • hyperfiltration
  • hypophosphatemia
  • renal functional reserve

ASJC Scopus subject areas

  • Physiology

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