[Effects of prolactin on chloremia and HCO3 dependant ATPase activities in kidney and gill of grey mullet, chelon Labrosus, during fresh water adaptation (author's transl)].

Only in SW fish, Prolactin (PRL) treatment increased natremia and especially chloremia. In gill, the decreases of Mg++ ATPase and SCN-sensitive, HCO3-ATPase observed in control fish after transfert from SW to FW, were more marqued in FW 8 days PRL treated fish. Renal enzyme activities were not affected by PRL treatment. If PRL treatment acts effectively on branchial ionic extrusion mechanisms, the connection between HCO3-ATPase anc Cl--transport remains to be elucidated. These results can be explained with reference to existence of two chloride-cell types.