Changes in concentrations of respiratory components and cytochrome oxidase activity in mitochondria obtained from carbon tetrachloride-induced cirrhotic rat liver.

Abstract

1. Changes in the concentrations of respiratory components, phosphorylative activity, the cytochrome oxidase activity of mitochondria and the hepatic adenylate energy charge level (in situ) were studied in cirrhotic rat liver induced by carbon tetrachloride (CCl4). 2. In the cirrhotic liver mitochondria, concentrations of cytochrome a(+a3), cytochrome b, coenzyme Q9 and coenzyme Q10 increased significantly to 2.44 +/- 0.02 x 10(-10) (mean +/- SE), 1.37 +/- 0.05 x 10(-10), 25.57 +/- 0.47 x 10(-10) and 5.39 +/- 0.26 x 10(-10) mol/mg of mitochondrial protein, respectively, compared with 1.83 +/- 0.03 x 10(-10), 1.22 +/- 0.02 x 10(-10), 16.24 +/- 0.39 x 10(-10) and 1.81 +/- 0.07 x 10(-10) in normal rats [P less than 0.001 for cytochrome a(+a3), coenzyme Q9 and coenzyme Q10, and P less than 0.01 for cytochrome b]. 3. Concentrations of flavoprotein and pyridine nucleotides decreased significantly to 13.33 +/- 0.14 x 10(-10) and 45.68 +/- 1.59 x 10(-10) mol/mg of mitochondrial protein, respectively, compared with 14.79 +/- 0.33 x 10(-10) and 86.26 +/- 1.83 x 10(-10) in normal rats (P less than 0.001). There was no significant difference in the concentration of cytochrome c(+c1). 4. Cytochrome oxidase activity per unit of cytochrome a(+a3) increased significantly to 67.43 +/- 1.71 atoms O s-1 mol-1, compared with 55.77 +/- 1.16 in normal rats (P less than 0.001). By contrast, phosphorylative activity per unit of cytochrome a(+a3) decreased significantly in the cirrhotic liver to 10.40 +/- 0.36 s-1 compared with 13.43 +/- 0.49 in normal rats (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)