RT Journal Article
SR Electronic
T1 Possible Mechanism of Hepatocyte Injury Induced by Diphenylamine and Its Structurally Related Nonsteroidal Anti-Inflammatory Drugs
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 982
OP 987
VO 292
IS 3
A1 Yasuhiro Masubuchi
A1 Shoko Yamada
A1 Toshiharu Horie
YR 2000
UL http://jpet.aspetjournals.org/content/292/3/982.abstract
AB Diphenylamine is a common structure of nonsteroidal anti-inflammatory drugs (NSAIDs) to uncouple mitochondrial oxidative phosphorylation and to cause a decrease in hepatocellular ATP content and hepatocyte injury. The mechanism for acute cell injury induced by diphenylamine and its structurally related NSAIDs was investigated with rat liver mitochondria and freshly isolated hepatocytes, focusing on the relation to the uncoupling of oxidative phosphorylation. Incubation of mitochondria with diphenylamine as well as mefenamic acid and diclofenac caused pseudoenergetic mitochondrial swelling, indicating that these compounds induce mitochondrial membrane permeability transition. Diphenylamine also caused changes in safranine-binding spectra to mitochondria that was energized by succinate oxidation. This spectral shift indicates the loss of mitochondrial membrane potentials, which is known as one of the characteristics for uncouplers of oxidative phosphorylation, and also was caused by mefenamic acid and diclofenac. Incubation of hepatocytes with mefenamic acid, diclofenac, and diphenylamine diminished cellular ATP content, followed by leakage of lactose dehydrogenase from hepatocytes. Fructose, a lowKm substrate for glycolysis, partially protected against the ATP depletion and hepatocyte injury induced by these compounds. Further addition of oligomycin, which blocks ATPase, pronounced the protection against cell injury. These results suggested that decreases in cellular ATP content, mainly caused by uncoupling of mitochondrial oxidative phosphorylation, were responsible for acute hepatocyte injury induced by diphenylamine and structurally related NSAIDs. The American Society for Pharmacology and Experimental Therapeutics