Unbound MEDLINE

Ethylene glycol induces hyperoxaluria without metabolic acidosis in rats.

Abstract

Ethylene glycol (EG) consumption is commonly employed as an experimental regimen to induce hyperoxaluria in animal models of calcium oxalate nephrolithiasis. This approach has, however, been criticized because EG overdose induces metabolic acidosis in humans. We tested the hypothesis that EG consumption (0.75% in drinking water for 4 wk) induces metabolic acidosis by comparing arterial blood gases, serum electrolytes, and urinary chemistries in five groups of Sprague-Dawley rats: normal controls (CON), those made hyperoxaluric (HYP) with EG administration, unilaterally nephrectomized controls (UNI), unilaterally nephrectomized rats fed EG (HRF), and a metabolic acidosis (MA) reference group imbibing sweetened drinking water (5% sucrose) containing 0.28 M NH4Cl. Arterial pH, plasma bicarbonate concentrations, anion gap, urinary pH, and the excretion of titratable acid, ammonium, phosphate, citrate, and calcium in HYP rats were not significantly different from CON rats, indicating that metabolic acidosis did not develop in HYP rats with two kidneys. Unilateral nephrectomy alone (UNI group) did not significantly affect arterial pH, plasma bicarbonate, anion gap, or urinary pH compared with CON rats; however, HRF rats exhibited some signs of a nascent acidosis in having an elevated anion gap, higher phosphate excretion, lower urinary pH, and an increase in titratable acid. Frank metabolic acidosis was observed in the MA rats: decreased arterial pH and plasma HCO3(-) concentration with lower urinary pH and citrate excretion with elevated excretion of ammonium, phosphate and, hence, titratable acid. We conclude that metabolic acidosis does not develop in conventional EG treatments but may ensue with renal insufficiency resulting from an oxalate load.

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  • Authors

    Green ML, Hatch M, Freel RW

    Source

    American journal of physiology. Renal physiology 289:3 2005 Sep pg F536-43

    MeSH

    Acidosis
    Animals
    Carbon Dioxide
    Disease Models, Animal
    Electrolytes
    Ethylene Glycol
    Hyperoxaluria
    Kidney Calculi
    Kidney Failure, Chronic
    Kidney Function Tests
    Male
    Oxalates
    Oxygen
    Rats
    Rats, Sprague-Dawley

    Pub Type(s)

    Journal Article
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't
    Research Support, U.S. Gov't, P.H.S.

    Language

    eng

    PubMed ID

    15855660