ANTIOXIDANT AND GLUTATHIONE-ASSOCIATED ENZYMES IN WILMS-TUMOR AFTER CHEMOTHERAPY

The present study demonstrates the activities of antioxidant and gluta thione-associated enzymes and the level of glutathione in Wilms' tumou r (nephroblastoma) samples after chemotherapy (mainly actinomycin D an d vincristine). We observed higher activity of superoxide dismutase in Wilms' tumour compared to adjacent morphologically unchanged kidney. On the other hand, in this tumour lower activities of catalase and the glutathione-associated enzymes glutathione synthetase, gamma-glutamyl transpeptidase, glutathione reductase and total glutathione S-transfe rases (GST) were found. Using isoelectric focusing we separated differ ent forms of GST in tested tissues and revealed lower activities of th e basic enzymes in Wilms' tumour, which may be responsible for the dec rease of total GST activity. Moreover, we found the acidic isoenzymes to be the predominant class of GST in nephroblastoma. In Wilms' tumour s with unfavourable histology a high activity of these isoenzymes toge ther with a high level of GSH were observed. We suggest that these par ameters may participate in the known phenomenon of anticancer drug res istance of tumours with unfavourable histology.