THE INDUCTION OF METALLOTHIONEIN IN TISSUES OF THE NORWAY LOBSTER NEPHROPS-NORVEGICUS FOLLOWING EXPOSURE TO CADMIUM, COPPER AND ZINC - THE RELATIONSHIPS BETWEEN METALLOTHIONEIN AND THE METALS

Nephrops norvegicus were exposed simultaneously to cadmium, copper and zinc over an 18-day period. Exposure concentrations were control, 1, 5 and 25 mu g litre(-1) for cadmium and copper and 8, 40 and 200 mu g litre(-1) for zinc. Concentrations of cadmium, copper, zinc and metall othionein were measured in homogenates of both the gill and the hepato pancreas. Quantification of metallothionein was carried out by differe ntial pulse polarography. Cadmium concentrations increased significant ly in the gill and hepatopancreas of both male and female animals in r esponse to increases in exposure concentration. In contrast, the conce ntration of copper and zinc increased significantly in the gills of ma les, but not in females. In the hepatopancreas, neither copper nor zin c resulted in significant changes in concentrations of these metals. M etallothionein concentrations in the gill and hepatopancreas were incr eased significantly in relation to metal exposure in both males and fe males. Concentrations of cadmium and metallothionein in both the gill and hepatopancreas of males and females were positively correlated. Co pper in the hepatopancreas also showed positive relationships with MT concentrations in males, but not in females. This study suggested that cadmium MTs in the gill and hepatopancreas of Nephrops norvegicus cou ld be used as a sensitive tool to detect cadmium contamination in the lobsters, although this was not true for copper and zinc. (C) 1997 Els evier Science Ltd.