Copper and Zinc Inhibit Chloride Transport Across the Opercular Epithelium of Seawater-Adapted Killifish Fundulus Heteroclitus

Abstract

ABSTRACT Effects of heavy metals on osmoregulation in aquatic organisms have recently been reviewed by Bouquegneau & Gilles (1979). Whereas most of the data in the literature deal with the toxic effects of mercurials, only a few reports can be found on the toxicity of essential trace elements such as Cu and Zn. Rainbow trout exposed to lethal (Skidmore, 1970) and sublethal (Watson & Beamish, 1980) concentrations of Zn maintain a relatively constant internal ionic environment. On the other hand Lewis & Lewis (1971) showed, in the channel catfish, a decreased osmolarity of blood serum after treatment with either Cu or Zn, and Katz (1979) reported an increased Na efflux in freshwater teleosts exposed to heavy metals. An increased gill Na, K-ATPase activity was described in the Zn-treated rainbow trout (Watson & Beamish, 1980). Shephard & Simkiss (1978) showed, in the same species, an increase in the gill protein content of fish exposed to Cu and Zn. These data agree with reports from Cu-treated winter flounder (Baker, 1969) and from Zn-treated dogfish (Crespo, Soriano, Sam-pera & Balasch, 1981; Crespo, 1982) each of which shows an increase in the number of the gill chloride cells.