Reye's syndrome: The effect of patient serum on mitochondrial respiration in vitro

Serum from patients with Reye's Syndrome stimulated state 4 respiration in isolated rat liver mitochondria. Inhibitors of specific mitochondrial functions were tested as potential antagonists of the stimulatory effect of RS serum. Oligomycin, ruthenium red, rotenone and antimycin A were all ineffective in preventing the increase in state 4 respiration, but KCN completely abolished all respiratory activity in the presence of RS serum. We conclude that the putative serum factor stimulates respiration by directly or indirectly interacting with the electron transport chain at a point beyond site II.