Translocase inhibition in endotoxic shock: a late step in the sequence of lethal events

Mitochondrial function in shock

Studies utilizing animal models of circulatory shock have revealed mitochondrial structural and functional damage in the liver, kidney, and brain. Adenosine triphosphate (ATP) synthesis and calcium transport rates of these mitochondria decline significantly during circulatory shock. The specific enzyme functions affected deleteriously by low flow states are the ATP synthetase, adenine nucleotide translocase, and carrier-mediated calcium transport. Other cellular alterations that possibly are responsible for, or are related to, the shock-induced mitochondrial deterioration are discussed. Differences in the mitochondrial responses to endotoxemia and hyperdynamic sepsis are described. Data are presented on the beneficial effects of early glucocorticoid treatment in prevention of mitochondrial functional deterioration during endotoxemia.

Early cutback in chemical energy production if the Crocker sarcoma (S180) undergoing haemorrhagic necrosis as a result of endotoxin administration

Alterations in the tumor adenine nucleotide pattern (TANP) have been measured at various times in a solid murine tumor undergoing haemorrhagic necrosis in vivo as a consequence of endotoxin administration. The ATP level fell rapidly in the first few hours; the AMP content initially rose, but began to fall back at 4 h. Overall adenine nucleotide losses occurred promptly, with only 4% of the original amount remaining at 24 h. Levels of glucose, glucose 6-phosphate, pyruvate, and lactate were also measured, and, with the exception of lactate, were for the most part lower in tumors from endotoxin-treated animals. Only minor alterations in the adenine nucleotide pattern were seen after either 4 or 24 h in the livers of normal or tumor-bearing mice in response to endotoxon injection, even when the creatures were moribund. The changes reported in the tumor are believed to have arisen not as a result of capillary stasis, but from prompt and selective disturbances to mitochondrial function in the tumor which have been described previously (Jones, 1977b, 1979).

Early mitochondrial damage in the induction of haemorrhagic necrosis in the Crocker sarcoma (S 180) by endotoxin

Disturbances in the functional properties of tumor mitochondria have been studied during the course of induction of haemorrhage brought about by endotoxin in the murine Crocker sarcoma (S 180). Extensive impairment of function was already present in mitochondria isolated from control tumors, as shown by low respiratory control ratios. The existing mitochondrial damage intensified promptly in response to injection of endotoxin long before the onset of haemorrhage at 4 h. The nature of the additional damage took two forms, depending on the duration of exposure to endotoxin; first, at 30 min, a true uncoupling of oxidative phosphorylation was seen, largely reversible in vitro by pre-treatment of the isolated organelles with bovine serum albumin (BSA). Second, at 1 h and later, oxygen utilisation in the presence of succinate, ADP and inorganic phosphate (Pi) was depressed. The pre-addition of BSA consistently lowered respiration rates with succinate and Pi in all preparations. The extent of endogenous inhibition of the adenine nucleotide translocase appeared unaltered by endotoxin in vivo.