| Ureagenesis: evidence for a lack of hepatic regulation of acid-base equilibrium in humans. | |
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MedLine Citation:
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PMID: 14656759 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Ureagenesis in the liver consumes up to 1,000 mmol of HCO3-/day in humans as a result of 2NH4+ + 2HCO3- --> urea + CO2 + 3H2O. Whether the liver contributes to the regulation of acid-base equilibrium by controlling the rate of ureagenesis and, therefore, HCO3- consumption in response to changes in plasma acidity has not been adequately evaluated in humans. Rates of ureagenesis were measured in eight healthy volunteers during control, chronic metabolic acidosis (induced by oral administration of CaCl2 3.2 mmol.kg body wt-1.day-1 for 11 days), and recovery as well as during bicarbonate infusion (200 mmol over 240 min; acute metabolic alkalosis). Rates of ureagenesis were correlated negatively with plasma HCO3- concentration both during adaption to metabolic acidosis and during the chronic, steady-state phase. Thus ureagenesis, an acidifying process, increased rather than decreased in metabolic acidosis. During bicarbonate infusion, rates of ureagenesis decreased significantly. Thus ureagenesis did not appear to be involved in the regulated elimination of excess HCO3-. The finding of a negative correlation between ureagenesis and plasma HCO3- concentration over a wide range of HCO3- concentrations, altered both chronically and acutely, suggests that the ureagenic process per se is maladaptive for acid-base regulation and that ureagenesis has no discernible homeostatic effect on acid-base equilibrium. |
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Authors:
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Markus Hosch; Juergen Muser; Henry N Hulter; Reto Krapf |
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Publication Detail:
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Type: Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: American journal of physiology. Renal physiology Volume: 286 ISSN: 1931-857X ISO Abbreviation: Am. J. Physiol. Renal Physiol. Publication Date: 2004 Jan |
Date Detail:
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Created Date: 2003-12-05 Completed Date: 2004-02-10 Revised Date: 2011-04-28 |
Medline Journal Info:
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Nlm Unique ID: 100901990 Medline TA: Am J Physiol Renal Physiol Country: United States |
Other Details:
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Languages: eng Pagination: F94-9 Citation Subset: IM |
Affiliation:
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Department of Medicine, Kantonsspital Bruderholz, CH 4101 Bruderholz/Basel, Switzerland. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acid-Base Equilibrium
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physiology* Acidosis / chemically induced, physiopathology Adult Alkalosis / chemically induced, physiopathology Bicarbonates / administration & dosage, blood Calcium Chloride / administration & dosage Homeostasis / physiology Humans Liver / physiology* Male Urea / metabolism* |
| Chemical | |
Reg. No./Substance:
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0/Bicarbonates; 10043-52-4/Calcium Chloride; 57-13-6/Urea |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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