Effect of cadmium exposure on zinc levels in the brine shrimp Artemia parthenogenetica

Zinc and cadmium have been reported as metabolic antagonists, such that hig h zinc intake afford animals some protection against the potentially toxic effects of cadmium exposure. There is considerable evidence to support a ro le of metallothioneins (MTs) in regulating or controlling the intracellular availability of essential metals and the non-essential metal. The effect o f 24-h cadmium pre-exposure (10 mg Cd/l) on zinc concentrations in the brin e shrimp Artemia parthenogenetica exposed to zinc (5 mg Zn/l) was studied. The zinc content of shrimps was not altered by cadmium. The homeostatic mec hanism for zinc regulation appears not to be disturbed by cadmium exposure in shrimps kept in naturally occurring zinc concentrations. When zinc was a dded to the water after cadmium exposure, the zinc concentrations attained by cadmium treated animals were lower than that of the non-exposed to cadmi um. No effect of zinc exposure on cadmium elimination was observed. In orde r to investigate the potential role of metallothionein in this effect, meta llothionein levels were measured and protein bound zinc and cadmium were st udied. A clear relationship between cadmium/zinc interactions with metallot hionein content or metal bound to this protein was not evident. (C) 1999 El sevier Science B.V, All rights reserved.