Metabolic acidosis inhibits pyruvate oxidation in chick liver by decreasing activity of pyruvate dehydrogenase complex.
Replacement of drinking water with NH4Cl (1.5%) solution significantly reduced blood pH on the 2nd d in chicks and thereafter. Concomitant with this reduction, oxidation rate of state 3 with pyruvate in liver mitochondria was also decreased in acidotic animals when compared with control animals. No significant differences between the two groups were observed in the state 4 oxidation at any feeding period. The ADP/O ratio did not appear to be affected by the treatment. The successive experiments of gavage-feeding for 4 d were also employed to ensure an equivalent intake of diet and the amount of NH4Cl given. As a result, the higher the NH4Cl provided, the lower the oxidation rate of state 3 with pyruvate in liver mitochondria, and the actual activity of pyruvate dehydrogenase complex, as expressed as units of produced CO2 per g wet weight of liver, which were accompanied by the lower pH in blood. This study provides the first evidence for a critical role of pyruvate dehydrogenase complex in the regulation of pyruvate catabolism in the liver from acidotic chicks induced by NH4Cl.
Science of Biological Function, Major of Life Science, Graduate School of Agriculture, Tohoku University, Sendai, Japan. toyomizu@bios.tohoku.ac.jp
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Toyomizu
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Yamahira
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Shimomura
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Akiba
D000138:Acidosis / Q000139:chemically induced / Q000201:enzymology / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000643:Ammonium Chloride / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000097:blood; D001835:Body Weight / Q000187:drug effects; D002339:Carotid Arteries; D002645:Chickens; D002950:Citrate (si)-Synthase / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D010084:Oxidation-Reduction; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010100:Oxygen / Q000378:metabolism; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism*; D014680:Veins
D001639:Bicarbonates; D011768:Pyruvate Dehydrogenase Complex; D000643:Ammonium Chloride; D000244:Adenosine Diphosphate; D019289:Pyruvic Acid; D000255:Adenosine Triphosphate; D002950:Citrate (si)-Synthase; D010100:Oxygen