Cadmium-induced metallothionein in earthworms (Lumbricus terrestris)

Studies are continuing to compare the common earthworm (Lumbricus terrestris) to rodents by their reactions to toxic levels of metals. A recent study suggests that LD50 of selenium compounds were about ten times less in worms than in rodents, but the toxicity of cadmium was of the same order of magnitude between these diverse species. An interesting finding is that the common earthworm produces a Cd-bound protein, metallothionein, after the injection of cadmium salts, and, similar to rodents, two Cd-bound isoproteins can be isolated by a Sephacryl S-200 column and monitored by both atomic absorption and liquid scintillation spectroscopy.