Abstract
Rainbow trout were exposed to defined levels of cadmium in their aquarium water for differing periods at a variety of near-lethal concentrations that ensured the survival of the majority of the fish. The gills, liver and kidney together accounted for 99% of the accumulated load of body cadmium in the fish under these conditions. Although the proportion of total cadmium present in the liver remained relatively constant throughout, the distribution of the remainder between gill and kidney altered with the time of exposure. The cadmium in all three organs was bound by two low molecular weight proteins distinct in character from metallothionein. The isoforms of metallothionein were also present but were found to bind only zinc and copper. By contrast, when trout were injected with cadmium intraperitoneally, most of the metal accumulated in the liver where it was sequestered by the two isoforms of metallothionein. Pre-exposure of the trout to either a low concentration of cadmium (for several months) or to an elevated concentration of zinc (for 5 days) allowed the animals to survive a subsequent exposure to a high, otherwise lethal concentration of cadmium. The proteins responsible for sequestration of the two metals were identified, but two different mechanisms seemed to be involved in the protection of the animals. The significance of these observations in terms of the induction of proteins and the prevention of the toxic effects of cadmium is considered.
Full text
PDF






Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Dohi Y., Ohba K., Yoneyama Y. Purification and molecular properties of two cadmium-binding glycoproteins from the hepatopancreas of a whelk, Buccinum tenuissimum. Biochim Biophys Acta. 1983 May 30;745(1):50–60. doi: 10.1016/0167-4838(83)90169-3. [DOI] [PubMed] [Google Scholar]
- Overnell J., Coombs T. L. Purification and properties of plaice metallothionein, a cadmium-binding protein from the liver of the plaice (Pleuronectes platessa). Biochem J. 1979 Nov 1;183(2):277–283. doi: 10.1042/bj1830277. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Post C. T., Squibb K. S., Fowler B. A., Gardner D. E., Illing J., Hook G. E. Production of low molecular weight cadmium-binding proteins in rabbit lung following exposure to cadmium chloride. Biochem Pharmacol. 1982 Sep 15;31(18):2969–2975. doi: 10.1016/0006-2952(82)90271-4. [DOI] [PubMed] [Google Scholar]
- Roberts K. S., Cryer A., Kay J., Solbe J. F., Wharfe J. R., Simpson W. R. The effects of exposure to sub-lethal concentrations of cadmium on enzyme activities and accumulation of the metal in tissues and organs of rainbow and brown trout (Salmo gairdneri, Richardson and Salmo trutta Fario L.). Comp Biochem Physiol C. 1979;62C(2):135–140. doi: 10.1016/0306-4492(79)90001-7. [DOI] [PubMed] [Google Scholar]
- Roberts K. S., Cryer A., Kay J., de L G Solbe J. F. A high-molecular-weight cadmium-binding fraction isolated from the liver cytosol of trout exposed to environmentally relevant concentrations of the metal [proceedings]. Biochem Soc Trans. 1979 Aug;7(4):650–651. doi: 10.1042/bst0070650. [DOI] [PubMed] [Google Scholar]
- Thomas D. G., Brown M. W., Shurben D., Solbe J. F., Cryer A., Kay J. A comparison of the sequestration of cadmium and zinc in the tissues of rainbow trout (Salmo gairdneri) following exposure to the metals singly or in combination. Comp Biochem Physiol C. 1985;82(1):55–62. doi: 10.1016/0742-8413(85)90209-9. [DOI] [PubMed] [Google Scholar]
- Thomas D. G., Cryer A., Solbe J. F., Kay J. A comparison of the accumulation and protein binding of environmental cadmium in the gills, kidney and liver of rainbow trout (Salmo gairdneri Richardson). Comp Biochem Physiol C. 1983;76(2):241–246. doi: 10.1016/0742-8413(83)90072-5. [DOI] [PubMed] [Google Scholar]
- Thomas D. G., Solbe J. F., Kay J., Cryer A. Environmental cadmium is not sequestered by metallothionein in rainbow trout. Biochem Biophys Res Commun. 1983 Jan 27;110(2):584–592. doi: 10.1016/0006-291x(83)91190-7. [DOI] [PubMed] [Google Scholar]
- Vander Mallie R. J., Garvey J. S. Radioimmunoassay of metallothioneins. J Biol Chem. 1979 Sep 10;254(17):8416–8421. [PubMed] [Google Scholar]
- Waalkes M. P., Chernoff S. B., Klaassen C. D. Cadmium-binding proteins of rat testes. Characterization of a low-molecular-mass protein that lacks identity with metallothionein. Biochem J. 1984 Jun 15;220(3):811–818. doi: 10.1042/bj2200811. [DOI] [PMC free article] [PubMed] [Google Scholar]