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.
Toyomizu
M
M
Science of Biological Function, Major of Life Science, Graduate School of Agriculture, Tohoku University, Sendai, Japan. toyomizu@bios.tohoku.ac.jp
Yamahira
S
S
Shimomura
Y
Y
Akiba
Y
Y
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