Determination of the activities of Na+/K+-ATPase , Ca+2-ATPase and mg+2-ATPase in tissues of fish (Oreochromis niloticus) exposed to Ca+2, Pb+2 ve Ca+2+ Pb+2

Freshwater fish (Oreochromis niloticus) was individually exposed to Ca2+, Pb2+ and Ca2++Pb2+ in different concentrations and exposure periods. At the end of exposure periods, Na+/K+-ATPase and Mg2+-ATPase activities in the gills and intestine and Ca2+-ATPase activity in the muscle were measured. There were changes in ATPase activities in relation to Ca2+ and Pb2+ concentration, exposure time and tissue type in both acute (48 hours, 20 ?M Pb2+) and chronic (14 days, 10 ?M Pb2+) exposure periods. ATPase activities were found to be higher in control group exposed to higher Ca2+ concentration comparing to the group exposed to lower Ca2+ concentration. Generally, ATPase activities increased in fish exposed to only Ca2+ concentration, while they showed both increases and decreases after exposure to Ca2++Pb2+. While gill Na+/K+-ATPase activity showed opposite reactions, the others showed similar trend in acute and chronic periods.