title: Mechanisms used to dispose of progressively increasing alkali load in rats.
abstract: Our objective was to describe the process of alkali disposal in rats. Balance studies were performed while incremental loads of alkali were given to rats fed a low-alkali diet or their usual alkaline ash diet. Control groups received equimolar NaCl or KCl. Virtually all of the alkali was eliminated within 24 h when the dose exceeded 750 micromol. The most sensitive response to alkali input was a decline in the excretion of NH(4)(+). The next level of response was to increase the excretion of unmeasured anions; this rise was quantitatively the most important process in eliminating alkali. The maximum excretion of citrate was approximately 70% of its filtered load. An even higher alkali load augmented the excretion of 2-oxoglutarate to >400% of its filtered load. Only with the largest alkali load did bicarbonaturia become quantitatively important. We conclude that renal mechanisms eliminate alkali while minimizing bicarbonaturia. This provides a way of limiting changes in urine pH without sacrificing acid-base balance, a process that might lessen the risk of kidney stone formation.
authors: Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada M5B 1A6.
authors: Surinder
authors: S
authors: Cheema-Dhadli
authors: Shih-Hua
authors: SH
authors: Lin
authors: Mitchell L
authors: ML
authors: Halperin
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology*; D000284:Administration, Oral; D000468:Alkalies / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics*; D000818:Animals; D000838:Anions / Q000378:metabolism; D001639:Bicarbonates / Q000378:metabolism; D002412:Cations / Q000378:metabolism; D019343:Citric Acid / Q000378:metabolism / Q000652:urine; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D007274:Injections, Intraperitoneal; D007656:Ketoglutaric Acids / Q000378:metabolism; D007668:Kidney / Q000502:physiology; D008297:Male; D011189:Potassium Chloride / Q000008:administration & dosage; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000008:administration & dosage
chemical_list: D000468:Alkalies; D000838:Anions; D001639:Bicarbonates; D002412:Cations; D007656:Ketoglutaric Acids; D000644:Quaternary Ammonium Compounds; D019343:Citric Acid; D012965:Sodium Chloride; D011189:Potassium Chloride