Branchial Na+ -K+ -ATPase activity in freshwater or saltwater acclimated tilapia, Oreochromis (Sarotherodon) mossambicus: effects of cortisol and thyroxine.

The ability of cortisol to stimulate branchial Na+ -K+ -ATPase activity in tilapia was further augmented by thyroxine. The effects of hormonal treatments were greater in the saltwater acclimated fish than in the freshwater acclimated ones.