Acute effects of acidosis on protein and amino acid metabolism in perfused rat liver

Acidosis is frequently associated with protein wasting and derangements in amino acid metabolism. As its effect on protein metabolism is significantly modulated by other abnormal metabolic conditions caused by specific illnesses, it is difficult to separate out the effects on protein metabolism sole...

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Bibliographic Details
Published in:International journal of experimental pathology 2003-08, Vol.84 (4), p.185-190
Main Authors: HOLECEK, Milan, SAFRANEK, Roman, RYSAVA, Radana, KADLCIKOVA, Jana, SPRONGL, Ludek
Format: Article
Language:English
Subjects:
acidosis
Acidosis - metabolism
Amino Acids - metabolism
Animals
Biological and medical sciences
Hydrogen-Ion Concentration
leucine
Leucine - metabolism
liver
Liver - metabolism
Male
Medical sciences
Metabolic diseases
Miscellaneous
Organ Culture Techniques
Original
Other metabolic disorders
protein synthesis
Proteins - metabolism
proteolysis
Rats
Rats, Wistar
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Summary:Acidosis is frequently associated with protein wasting and derangements in amino acid metabolism. As its effect on protein metabolism is significantly modulated by other abnormal metabolic conditions caused by specific illnesses, it is difficult to separate out the effects on protein metabolism solely due to acidosis. The aim of the present study was to evaluate, using a model of isolated perfused rat liver, the direct response of hepatic tissue to acidosis. We have compared hepatic response to perfusion with a solution of pH 7.2 and 7.4 (controls). Parameters of protein and amino acid metabolism were measured using both recirculation and single‐pass technique with 4,5‐[3H]leucine, [1–14C]leucine and [1–14C]ketoisocaproate (ketoleucine) as tracers and on the basis of difference of amino acid levels in perfusion solution at the beginning and end of perfusion. In liver perfused with a solution of pH 7.2, we observed higher rates of proteolysis, protein synthesis, amino acid utilization and urea production. Furthermore, the liver perfused with a solution of pH 7.2 released a higher amount of proteins to perfusate than the liver perfused with a solution of pH 7.4. Enhanced decarboxylation of ketoisocaproate in liver perfused by a solution of a lower pH indicates increased catabolism of branched‐chain amino acids (leucine, valine and isoleucine), decreased reamination of branched‐chain keto acids to corresponding essential amino acids and increased ketogenesis from leucine.
ISSN:0959-9673
1365-2613
DOI:10.1046/j.1365-2613.2003.00352.x