Differences in inducibility of particulate and cytosolic rat liver glutathione S-transferase activities.

1. Rat liver mitochondrial microsomal glutathione (GSH) S-transferase activities with 1-chloro-2,4-dinitrobenzene as substrate were 11.0 and 11.6%, and with 1,2-dichloro-4-nitrobenzene as substrate were 27.7 and 15.4%, of the corresponding cytosolic activities respectively. 2. Marked difference in inducibility of cytosolic and particulate GSH S-transferase activities were seen after pretreatment of animals with enzyme-inducing agents. 3-Methylcholanthrene and 2,3,7,8-tetrachlorodibenzo-p-dioxin enhanced cytosolic GSH S-transferase activity only. Phenobarbital induced the cytosolic and microsomal enzymes only.