Inhibition by perhexiline of oxidative phosphorylation and the beta-oxidation of fatty acids: possible role in pseudoalcoholic liver lesions.

In an attempt to better understand the mechanisms for pseudoalcoholic liver lesions in human beings, we determined the effects of perhexiline on mitochondrial functions in mice and rats. A first series of studies suggested that protonated perhexiline entered mouse mitochondria along the mitochondrial membrane potential. Release of a proton in the mitochondrial matrix led to uncoupling of oxidative phosphorylation, and accumulation of perhexiline inhibited complexes I and II of the respiratory chain, decreased ATP formation in vitro and decreased the mitochondrial beta-oxidation of long-, medium- and short-chain fatty acids in vitro and in vivo in mice. In cultured rat hepatocytes, exposure for 24 hr to 25 mumol/L perhexiline markedly decreased hepatocellular ATP and cell viability. Exposure to 5 mumol/L perhexiline did not modify ATP and viability but decreased the beta-oxidation of palmitic acid uniformly labeled with carbon 14 by 38%, increased hepatocyte triglyceride levels by 98% and produced microvesicular steatosis after 72 hr of culture. We conclude that perhexiline is concentrated inside mitochondria, where it inhibits both oxidative phosphorylation and the mitochondrial beta-oxidation of fatty acids. These effects may contribute to the development of necrosis, steatosis and possibly certain other pseudoalcoholic liver lesions in human beings.