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2-Ethylhexanol uncouples oxidative phosphorylation in rat liver mitochondria
B J Keller1, D Liang, R G Thurman
1Department of Pharmacology, University of North Carolina, Chapel Hill 27599-7365.
Toxicology Letters
|June 1, 1991
Summary
2-Ethylhexanol, a chemical pollutant, impairs liver function by disrupting cellular respiration and energy production, leading to cell death. This study reveals its mechanism involves uncoupling oxidative phosphorylation in mitochondria.
Area of Science:
- Hepatotoxicity and Toxicology
- Mitochondrial Physiology
- Biochemical Pharmacology
Background:
- 2-Ethylhexanol is a non-genotoxic carcinogen and peroxisome proliferator.
- Its effects on liver function and cellular energy metabolism are not fully understood.
Purpose of the Study:
- To investigate the impact of 2-Ethylhexanol on hepatic energy metabolism and mitochondrial function.
- To elucidate the mechanism by which 2-Ethylhexanol induces hepatotoxicity.
Main Methods:
- Perfusion of rat livers with varying doses of 2-Ethylhexanol.
- Measurement of oxygen uptake, lactate dehydrogenase (LDH) release, and adenine nucleotide levels.
- Assessment of 2-Ethylhexanol's effects on isolated mitochondria, including respiration rates, P/O ratio, and calcium uptake.
Main Results:
- Hepatotoxic doses of 2-Ethylhexanol caused a rapid inhibition of liver respiration and significant release of LDH.
- 2-Ethylhexanol markedly decreased the ATP/ADP ratio, indicating a collapse of the hepatic energy state.
- In isolated mitochondria, 2-Ethylhexanol acted as an uncoupling agent, decreasing coupled respiration and the P/O ratio, and inhibiting calcium uptake.
Conclusions:
- 2-Ethylhexanol-induced hepatotoxicity is preceded by a severe impairment of cellular energy metabolism.
- The mechanism involves the uncoupling of oxidative phosphorylation in mitochondria, leading to diminished ATP synthesis and disruption of ion gradients.
- These mitochondrial dysfunctions contribute to the observed liver cell death.