Integrity of liver inner mitochondrial membrane in rats with extrahepatic cholestasis

To investigate the effect of extrahepatic cholestasis on integrity of the inner mitochondrial membrane, a study was conducted on two groups of rats: sham-operated control animals (N = 10) and rats subjected to extrahepatic cholestasis (EHC, N = 10) by double ligation of the hepatic duct. The animals were observed for 7 days and then sacrificed. The EHC group presented significantly higher serum levels of alanine aminotransferase, total bilirubins and alkaline phosphatase than the controls (P less than 0.01). Basal mitochondrial respiration (state IV), analyzed separately using either alpha-ketoglutarate or alpha-ketoglutarate + pyruvate as substrates, was similar in the two groups (P greater than 0.01). ADP-activated respiration, state III, diminished significantly in the EHC group. The results show that the decrease in mitochondrial function that has been reported by several investigators to occur in EHC is due to mitochondrial alterations not related to the ability of these organelles to maintain the proton gradient, since the inner mitochondrial membrane continued to be energized throughout the observation period.