HEPATIC PHENYLALANINE-HYDROXYLASE OF BANK VOLES CLETHRIONOMYS-GLAREOLUS SCHREBER AS A BIOMARKER OF POLLUTION

In order to identify some novel parameters for monitoring tile environ mental impact of industrial pollutants, we measured the hepatic phenyl alanine hydroxylase activities of two species of feral rodent: the ban k vole Clethrionomys glareolus and field mouse Apodemus sylvaticus tra pped at two isolated rural areas (reference sites) and at a study site adjacent to a bauxite refinery where atmospheric sulphur dioxide leve ls are high. At the reference sites voles showed lower-specific activi ty for the enzyme than mice, There was no difference in activities bet ween mice from contaminated and reference sites, However, reference en zyme activities of both male and female voles were lower at the contam inated site, and males showed severe diminution of hepatic tetrahydrob iopterin-dependent phenylalanine hydroxylase (27% of reference values) . Western blotting revealed normal abundance of phenylalanine hydroxyl ase protein, indicating loss of catalytic function, Loss of activity m ay be due to oxidative stress resulting from an accompanying deficienc y in glutathione peroxidase activity, which for voles of both sexes at the contaminated site was half that of the references. The difference s between mice and voles are discussed. These two enzymes in bank vole s may provide useful bioindicators of the impact of industrial polluta nts.