ALTERED GLUTATHIONE TRANSFERASE LEVELS IN RAT SKIN INFLAMED DUE TO CONTACT HYPERSENSITIVITY - INDUCTION OF THE ALPHA-CLASS SUBUNIT-1

Since glutathione transferases (GSTs) are suggested to be involved in the prevention of tissue damage by oxidative stress,; quantitative and qualitative alterations of GST forms were examined in rat skin after induction of inflammation by 0.6 and 1 % 1-chloro-2,4-dinitrobenzene ( CDNB) treatment. With 0.6 % CDNB, the GST activity in supernatant prep arations was 1.8-fold higher than that for control skin, with most GST s in both cases being bound to S-hexyl-GSH-Sepharose. Major GST subuni ts of control skin were identified as subunits 7, 4 and 2 by HPLC and chromatofocusing at pH 11-7. These subunits were increased in inflamed skin by 0.6 % CDNB and, in addition, the subunit 1 of the Alpha class and subunit 6, both hardly detectable in control skin, were expressed . The specific activity value for GST 7-7 from the inflamed skin by 0. 6 % CDNB was 2.4-fold lower than that from control skin. However, in t he case of inflamed skin after application of 1% CDNB, GST activity wa s decreased to 69 % of the control value and most activity was recover ed in fractions binding to a GSH-Sepharose but not a S- hexyl-GSH-Seph arose column. GSTs eluted from the former column demonstrated a restor ed capacity to bind to the latter, suggesting the GSTs in inflamed ski n to be partly inactivated and that they regained activity on exposure to GSH. The K-m and V-max values for GSH of GST 4-4 from inflamed ski n after 1 % CDNB treatment were 6-fold and 2-fold higher, respectively , than those for the enzyme from control skin, suggesting partial enzy me modification. These results suggest that not only quantitative but also qualitative alterations of GST subunits occur with CDNB-induced i nflammation in vivo.