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Published on: September 16, 2020
The effects of halothane on hepatic microsomal electron transfer
The Biochemical Journal
|May 1, 1975
Summary
Halothane, an anesthetic, alters liver microsomal electron transfer by oxidizing cytochrome b5. This effect is linked to the cyanide-sensitive stearate desaturase pathway, not cytochrome P-450.
Area of Science:
- Biochemistry
- Pharmacology
- Cellular Biology
Background:
- Halothane is a volatile anesthetic affecting cellular processes.
- Microsomal electron transfer is crucial for various metabolic pathways.
- Cytochrome b5 plays a role in redox reactions within microsomes.
Purpose of the Study:
- To investigate the impact of halothane on electron transfer in rat liver microsomes.
- To determine the specific mechanisms and pathways involved in halothane's effects.
- To differentiate halothane's action from cytochrome P-450 mediated metabolism.
Main Methods:
- Incubation of isolated rat liver microsomes with halothane at anesthetic concentrations (1-2mM).
- Measurement of NADPH and O2 consumption, and cytochrome b5 redox state.
- Assay of NADH- and NADPH-cytochrome c reductase activities and stearate desaturase activity.
Main Results:
- Halothane oxidized microsomal cytochrome b5 in the presence of NADPH.
- Accelerated consumption of NADPH and O2, and increased reoxidation of ferrocytochrome b5 were observed.
- Halothane's effects were potentiated by a high-carbohydrate diet and abolished by cyanide, implicating the stearate desaturase pathway.
Conclusions:
- Halothane's effects on microsomal electron transfer are independent of cytochrome P-450.
- The interaction of halothane with a cyanide-sensitive factor in the stearate desaturase pathway is responsible for the observed changes.
- These findings provide insight into the non-metabolic interactions of anesthetics at the cellular level.
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