title: Effect of phosphorus restriction on renal response to oral and intravenous protein loads in rats.
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 (CIn), p-aminohippuric acid clearance (CPAH), 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 CIn, CPAH, blood pressure, and RVR were similar. After albumin gavage, CIn 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.
authors: Division of Renal Medicine, Francis Scott Key Medical Center, Johns Hopkins School of Medicine, Baltimore, Maryland.
authors: E S
authors: ES
authors: Kraus
authors: L
authors: L
authors: Cheng
authors: I
authors: I
authors: Sikorski
authors: D A
authors: DA
authors: Spector
mesh_terms: D000284:Administration, Oral; D000596:Amino Acids / Q000008:administration & dosage / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D005215:Fasting; D005260:Female; D005934:Glucagon / Q000097:blood; D005998:Glycine / Q000008:administration & dosage; D006439:Hemodynamics / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D007444:Inulin / Q000378:metabolism; D007668:Kidney / Q000098:blood supply / Q000187:drug effects / Q000502:physiology*; D016226:Phosphorus, Dietary / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D012083:Renin / Q000097:blood; D014655:Vascular Resistance / Q000502:physiology; D010130:p-Aminohippuric Acid / Q000378:metabolism
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D016226:Phosphorus, Dietary; D007444:Inulin; D005934:Glucagon; D012083:Renin; D005998:Glycine; D010130:p-Aminohippuric Acid