In vivo changes in the activity of gill ATPases, muscle cell volume, and plasma and cellular ionic concentration of the African catfish, Clarias gariepinus induced by atrazine or DDT at different sublethal concentrations

الملخص EN

The study concerns the effects of the herbicide atrazine and the insecticide p,p'-DDT at different sublethal doses and during various test periods on branchial Na+, K*, Mg2 f-ATPase activities, ionic composition of the plasma and muscle and the volume of muscular cells in the african catfish Clarias gariepinus.

The most important significant changes in Na+, K*, ATPase activity during exposure to atrazine were represented by decrease at the lower concentration (100 jjLg/liter) and increase at the higher concentration (500 (xg/liter).

Exposure to 500 |xg/liter DDT produced a short and strong activation of gill Na , K+,- ATPase which was followed by recovery to controls level.

While -Mg* -ATPase was activated from exposure hr 72 at both atrazine concentrations, it was inhibited during the whole experimental time in DDT (24 hr).

Sodium and potassium concentrations in plasma and muscle cells as well as cell volume were changed during exposure to both chemicals, which might indicate osmoregulation difficulties.

The value of the measured responses as an indicator of stress caused by water contamination is discussed.