Biochemical alterations in juvenile carp (Cyprinus carpio) exposed to zinc:: Glutathione reductase as a target

The aim ofthis study was to investigate biochemical changes injuvenile carp (Cyprinus carpio) exposed to zinc chloride (10, 30 and 100 VM) for a period of 48 h. Zinc exposure caused a concentration-dependent reduction in glutathione reductase'(GR) activity in gills, liver and brain. Gill glutathione S-transferase (GST) was reduced when animals were exposed to the highest concentration of 100 pM zinc. The phosphorylation of p381APK increased in the brain of fish exposed to zinc 100 liM, while phosphorylation of the extracellular signal-regulated protein kinase 112 (ERKI/2) and c-Jun N-teriminal protein kinase 1/2 UNK1 /2) remained unchanged. Expression of proteins HSP60 and HSP70 were not affected by zinc exposure. Considering the significant concentration-dependent inhibition of GR in all tissues analyzed, this enzyme could be a potential biomarker of exposure to zinc, which has to be confirmed. (C) 2008 Elsevier Ltd. All rights reserved.