Glutathione S-transferase and UDP-glucuronyltransferase activity in primary cultures of rainbow trout gill epithelial cells

The objective of this study was to characterize rainbow trout (Oncorhynchus mykiss) fill epithelial cells in primary culture by evaluating their abili ty to maintain glutathione and glucuronide conjugating enzymes. The activit y and inducibility of the phase II enzymes was investigated as a function o f culture time. Glutathione S-transferase (GST) and UDP-glucuronyltransfera se (UDPGT) enzyme activities were measured in freshly isolated cells and in cells cultured for 7 and 12 days. GST activity, determined with 1-chloro-2 ,4-dinitrobenzene, decreased gradually to 72% after 7 days and to 38% after 12 days in culture compared with freshly isolated cells. There was no sign ificant difference between UDPGT activities in freshly isolated cells compa red with cells cultured up to 12 days although a transient decrease in acti vity was observed at day 7. In vitro induction of the enzymes was studied u sing beta -naphtoflavone (BNF) and 3-methylcholanthrene (3-MC) as inducers. GST activity increased 2-fold after exposure to BNF and 1.5-fold after 3-M C exposure for 48 h in 7 days old cultures. No induction was observed in 12 days old cultures. UDPGT activity was not induced either at day 7 or 12. ( C) 2000 Elsevier Science Inc. All rights reserved.