DETOXIFICATION OF EXOGENOUS COPPER BY BINDING TO HEMOLYMPH-PROTEINS IN THE SHORE CRAB, CARCINUS-MAENAS

Copper of exogenous origin is present in crab hemolymph mainly in a pr otein-bound form. Various approaches were used to assess the toxicity of this protein-bound exogenous metal. Mortality due to copper directl y injected into the hemolymph space was apparent at circulating concen trations of non-hemocyanic copper much higher than that (about 150 mu M) attained during exposure to a lethal level of waterborne copper (31 .5 mu M in water). No cytological damage to the gill epithelium was ap parent in crabs injected with the metal to attain a hemolymph exogenou s copper level of 150 mu M, in contrast to those observed at similar h emolymph concentrations during waterborne metal exposure. The cytotoxi city of copper added to an in vitro hepatopancreatic cell preparation was greatly diminished in the presence of hemolymph proteins, probably in relation to a reduced copper uptake by these cells. Thus, binding of copper to hemolymph proteins and particularly hemocyanin plays a si gnificant role, not only for transport and distribution, but also for detoxification of the metal within the organism.