Inhibition of hepatic glutathione-S-transferases by fatty acids and fatty acid esters.

Micromolar concentrations of polyunsaturated fatty acids and ascorbate esters of saturated fatty acids were found to cause a marked inhibition of rat and mouse hepatic glutathione-S-transferase (GST) activity towards 1-chloro-2,4-dinitrobenzene. Arachidonic acid was approximately 25 times more potent in inhibiting rat GST than palmitic acid which was the least effective. Both linoleic and arachidonic acids did not inhibit rat liver GST when ethacrynic acid was used as substrate while the reverse was true with 1,2-dichoro-4-nitrobenzene. In contrast, all the chemicals tested inhibited rat liver GST activity towards 4-nitropyridine N-oxide, indicating isozyme specificity.