Effects of atrazine, endosulfan and butylated hydroxyanisole on glutathione-S-transferases in Orthosia gothica

Atrazine (1000 ppm), endosulfan (1 ppm) or butylated hydroxyanisole (BHA) ( 1000 ppm) added to a semi-synthetic diet of Orthosia gothica for 2 days in the last instar did not change the soft tissue cytosolic glutathione-S-tran sferase (GST) activities towards 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-di chloro-4-nitrobenzene (DCNB) and cumene hydroperoxide (CU). However, all th ree pesticides changed the GST subunit composition compared with the contro l as observed by reverse phase high performance liquid chromatography of th e isozymes purified by glutathione-Sepharose affinity chromatography. The c hanges seem to have occurred mainly in the GST class 2 subunit. There is no obvious explanation for the changes, which may be a result of interactions between xenobiotic and GST in the cytosol as well as changes in the level of regulation of synthesis. However, the observation added to our knowledge of the processes involved when pesticides are degraded by GSTs in vivo. (C ) 2000 Published by Elsevier Science Inc.