CHANGES IN GST-ISOENZYME PATTERN OF SOME ORGANS OF SHEEP EXPOSED TO DIFFERENT LEVELS OF POLLUTION

GST isonzyme patterns were studied in the cytosolic fraction of liver, kidney and lung of sheep exposed to industrial metal pollutants and c ompared with those of control animals. The methodology included the de termination of enzymatic activities with several subunit-specific subs trates (DCNB, NPB, EPNP and EA) and Western blotting using antibodies to specific rat GST subunits 1, 8 (alpha class), 3 (mu class) and 7 (p i class). In liver and lung, crossed reactivities with subunits 1 and 3 were absent in the controls but were present in exposed animals. Jus t the opposite result was obtained for subunit 8 crossed reactivity th at was only in the control animals. In the kidney, crossed reactivitie s towards subunits 3 and 8 were absent and crossed reactivity equivale nt to subunit 7 was present in all animals, and equivalent to subunit 1 was weakly induced in exposed animals. A 3.3-fold increase in the ac tivity with NPB detected in the kidneys of exposed animals points to t he induction of a theta class isoenzymes. Clear increases were found i n the livers of exposed animals in the activities with CDNB (1.8-fold) , DCNB (2.6-fold) and EPNP (2.1-fold), but no differences were found i n the lungs with any of the substrates. The GST isoenzyme pattern of l iver and lung could be, in principle, a useful biomarker of exposure t o environmental pollution in sheep.