Enhanced glutathione S-transferase 7-7 expression in rat hepatic cytosol following treatment with pyrrole.
Rat hepatic GST 7-7 expression in cytosol and in the S-hexylglutathione-agarose affinity purified fraction of cytosol from saline- (control) and pyrrole-treated animals was examined using metabolic activity, SDS-PAGE, immunoblot, and HPLC analyses. Metabolic activity of hepatic cytosol from pyrrole-treated animals was assayed using the substrates 1-chloro-2,4-dinitrobenzene, ethacrynic acid, and acrolein, and an approximately 1.5-, 1.2-, and 1.3-fold increase, respectively, was monitored in the rate of GST-catalyzed substrate conjugation to reduced glutathione. SDS-PAGE and immunoblot analysis using Class Pi GST-specific IgG confirmed that the GST 7 subunit was expressed in hepatic cytosol and in the affinity purified fractions from pyrrole-treated rats. In contrast, the GST 7 subunit was below the limit of detection in hepatic cytosol of saline-treated animals. HPLC analysis demonstrated the presence of the GST 7 subunit in the affinity purified fraction from pyrrole-treated rat hepatic tissue and showed that the level of this subunit was increased approximately 8-fold relative to the barely detectable level present in control tissue. N-terminal amino acid sequencing analysis confirmed the identity of the HPLC peak as GST 7-7. GST subunits 3, 1a, and 1b were elevated approximately 1.7-, 2.0-, and 2.4-fold respectively, in response to pyrrole treatment. These data provide evidence that pyrrole treatment results in de novo expression of GST 7-7 in rat hepatic tissue and suggest that pyrrole-containing compounds potentially generated during disease and/or altered heme metabolism, or those ingested in food products, may alter GST expression in hepatic tissue.
Primiano
T
T
Institute of Chemical Toxicology, Wayne State University, Detroit, MI 48201.
Gandy
J
J
York
J L
JL
Novak
R F
RF
D000818:Animals; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000201:enzymology; D005982:Glutathione Transferase / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008297:Male; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013379:Substrate Specificity
D007527:Isoenzymes; D011758:Pyrroles; D005982:Glutathione Transferase