Stimulation of mouse liver glutathione S-transferase activity in propylthiouracil-treated mice in vivo by tri-iodothyronine.
Female C57Bl/6J mice were given drinking water containing 0.05% propylthiouracil to induce a hypothyroid condition. Mitochondrial glycerol-3-phosphate dehydrogenase activity, used as an index of hypothyroidism, was 57.1 +/- 4.5 and 29.4 +/- 3.8 nmol/min per mg of protein for control and propylthiouracil-treated animals respectively. Administration of tri-iodothyronine resulted in an approx. 4.5-fold increase in dehydrogenase activity in propylthiouracil-treated animals. A dose-dependent increase in hepatic GSH S-transferase activity in propylthiouracil-treated animals was observed at tri-iodothyronine concentrations ranging from 2 to 200 micrograms/100 g body wt. This increase in transferase activity was seen only when 1,2-epoxy-3-(p-nitrophenoxy)propane was used as substrate for the transferase. Transferase activity with 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene as substrate was decreased by tri-iodothyronine. Administration of actinomycin D (75 micrograms/100 g body wt.) inhibited the tri-iodothyronine induction of transferase activity. Results of these studies strongly suggest that tri-iodothyronine administration markedly affected the activities of GSH S-transferase by inducing a specific isoenzyme of GSH S-transferase and suppressing other isoenzymic activities.
D000818:Animals; D003609:Dactinomycin / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D004852:Epoxy Compounds / Q000378:metabolism; D005260:Female; D005982:Glutathione Transferase / Q000096:biosynthesis*; D007037:Hypothyroidism / Q000139:chemically induced; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009596:Nitrophenols / Q000378:metabolism; D011441:Propylthiouracil / Q000494:pharmacology*; D014284:Triiodothyronine / Q000494:pharmacology*
D004852:Epoxy Compounds; D009596:Nitrophenols; D014284:Triiodothyronine; D003609:Dactinomycin; D011441:Propylthiouracil; C007606:1,2-epoxy-3-(p-nitrophenoxy)propane; D005982:Glutathione Transferase