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Glutathione turnover in isolated hepatocytes
Acta Pharmacologica Et Toxicologica
|April 1, 1978
Summary
Hepatocytes depleted of glutathione (GSH) showed increased GSH synthesis when supplemented with amino acids. This suggests endogenous protein breakdown significantly contributes to hepatic cysteine levels for GSH production, especially during drug metabolism.
Area of Science:
- Biochemistry
- Cell Biology
- Hepatology
Background:
- Glutathione (GSH) is a critical endogenous antioxidant in hepatocytes.
- Diethylmaleate effectively depletes cellular GSH levels in vitro.
- Understanding GSH synthesis regulation is vital for liver health and drug metabolism.
Purpose of the Study:
- To investigate the factors influencing hepatic glutathione (GSH) synthesis rate.
- To determine the role of exogenous and endogenous amino acids in GSH production.
- To assess the impact of drug metabolism on hepatic cysteine pools.
Main Methods:
- Isolated hepatocytes were treated with diethylmaleate to induce GSH depletion.
- GSH accumulation rate was measured as an indicator of GSH synthesis.
- Uptake rates of methionine and cysteine were analyzed.
- The effects of amino acids and horse serum on GSH synthesis were evaluated.
Main Results:
- Diethylmaleate treatment reduced hepatocyte GSH content by approximately 50%.
- GSH synthesis rate increased within one hour post-treatment.
- Amino acids and horse serum influenced the GSH synthesis rate.
- Methionine and cysteine uptake rates were lower than GSH synthesis rates and unaffected by horse serum or GSH synthesis variations.
Conclusions:
- Exogenous sulfur-containing amino acids support GSH synthesis in hepatocytes.
- Hepatic cysteine pools are substantially replenished by endogenous amino acids from protein degradation.
- This endogenous supply is particularly important when drug metabolism increases cysteine pool turnover.