The high concentrations of cadmium recorded in the digestive gland of cephalopods from
various temperate and subpolar waters suggest that these molluscs have developed efficient
cadmium detoxification mechanisms. The subcellular distribution of cadmium in the digestive
gland cells was investigated in seven cephalopod species from the Bay of Biscay (France) and
the Faroe Islands. In most species, cadmium was mainly found in the cytosolic fraction of the
digestive gland cells, reaching up to 86% of the total cadmium for the squid Loligo vulgaris
from the Bay of Biscay. But species with the highest total level of cadmium showed a higher
percentage of cadmium associated to insoluble compounds. The quantification of metallothioneins
(MTs) by the polarographic method was performed in order to evaluate the
involvement of these proteins in the detoxification of the high amounts of bioaccumulated
cadmium. Metallothionein levels in cephalopods ranged form 742270 to 34781572 mg/g
wet weight. No relationship could be established between total cadmium, cytosolic cadmium
and MT levels suggesting the occurrence of other Cd-binding ligands. Although these proteins
have not been characterised, as cadmium in the digestive gland of cephalopods is mainly
associated with soluble ligands, a high potential transfer to predators can be predicted.#2002
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