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Acclimation to cadmium toxicity by white suckers: Cadmium binding capacity and metal distribution in gill and liver cytosol
Author(s) -
Klaverkamp J. F.,
Duncan D. A.
Publication year - 1987
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620060405
Subject(s) - metallothionein , cytosol , cadmium , toxicity , glutathione , acclimatization , chemistry , biochemistry , biology , enzyme , ecology , organic chemistry
Abstract Juvenile white suckers (Catostomus commersoni) were exposed for one week to Cd, Zn or Hg at concentrations previously reported to produce acclimation to levels of Cd that would normally induce lethality. Cytosolic fractions from liver and gill filaments were analyzed for their capacity to bind 109 Cd and for distribution of Cu, Zn, Cd and Hg. Binding of 109 Cd was increased in the cytosolic fraction (peak II), which would contain metallothionein (MTN) from liver of Cd‐exposed and Zn‐exposed fish, and from gill of Hg‐exposed and Zn‐exposed fish. This binding was also increased in the low molecular weight fraction (peak III), which would contain glutathione, from liver cytosol of all metal‐exposed fish and gill cytosol of Cd‐exposed fish. Increases in 109 Cd binding in peaks II and III were accompanied by decreases in 109 Cd binding in high molecular weight fractions (peak I) containing enzymes from liver cytosol of all metal‐exposed suckers and gill cytosol of Cd‐exposed fish. Exposures to Cd, Zn or Hg produced relative increases in their respective concentrations in peaks I and II, which corresponded to the order of potency (Hg > Cd >> Zn) for inducing acclimation to Cd toxicity. Concentrations of Zn, Cu, Cd and Hg in peak II were used to provide crude estimates of MTN concentrations. Values of 314 and 33 μg MTN/g tissue were obtained for liver and gill, respectively, from non‐exposed fish. Hg, the most potent inducer of acclimation to Cd toxicity, was the only metal that produced increased MTN concentrations in both liver and gill. Zn, the least potent inducer, produced the smallest increase in liver MTN and no increase in gill MTN. Further research that is required to understand the more complex relationships between acclimation to Cd toxicity and cytosolic metal‐binding proteins is discussed.