Effects of E. coli Endotoxin on Rat Liver Mitochondria. I. The Effects of E. coli Endotoxin on Isolated Rat Liver Mitochondria and Rat Liver Mitochondrial Functions Following Endotoxin Administration

The effects of E. coli endotoxin (Et) on isolated rat liver mitochondria and rat liver mitochondrial functions after Et shock were studied. The results were as follows. 1) Interaction of Et with intact mitochondria resulted in a loss of respiratory control ratio (RCR), decrease of ADP/O ratio and phosphorylative activity, toghther with an increase of ATPase activity and induction of mitochondrial swelling. A small dose of Et increased the succinate-cytochrome c reductase activity, whereas a large dose inhibited the activity. The content of respiratory enzymes was notinfluenced by Et. 2) During the 2 hours after administration of lethal Et (5mg/100g), RCR, ADP/O ratio and phosphorylative activity were unchanged, however, they decreased rapidly after 3 hours. The succinatecytochrome c reductase activity, the ATPase activity and the content of respiratory enzymes were not influenced throughout the course of the experiments. 3) The inhibition of mitochondrial respiration by Et was not seen in the experiments on liver slices in vitro. From these results, it may be considered that the cause of the liver mitochondrial dysfunctions after the administration of Et was to be sought in tissue hypoxia due to changes in the circulatory system rather than a direct effect of Et on mitochondrial membranes