title: Hepatic metallothionein and resistance to copper in juvenile coho salmon.
abstract: 1. Four groups of 600 juvenile coho salmon (Oncorhynchus kisutch) of 3-8g body weight were exposed to sublethal concentrations of copper acetate in water of hardness 280 mg/l (as CaCO3). 2. Flow-through conditions were maintained for a period of 10 weeks, during which the copper concentrations to which the groups of fish were exposed were approximately 1, 50, 100 and 150 micrograms Cu/l. 3. Hepatic metallothionein concentrations were measured using differential pulse polarography in filtrates of heat-denatured saline extracts of the tissues. 4. These values increased as a function of the copper concentration to maximum levels after 4 weeks of continuous exposure and thereafter remained more or less constant. 5. Flow-through 168 hr LC50 values for fish tested at intervals throughout the experiment increased to maximum values (2.5 X control values) at 1 week and during the next 3 weeks fell somewhat to stable but elevated values. 6. At 4 weeks, these were related to the metallothionein (MT) values by the regression equation 168 hr LC50 = 2.423 (+/- 0.455) X MT + 48.6 (+/- 31.1). 7. The probability that the relationship was not accidental exceeded 97%.
mesh_terms: D000818:Animals; D003300:Copper / Q000633:toxicity*; D007700:Kinetics; D007928:Lethal Dose 50; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008667:Metalloproteins / Q000378:metabolism*; D008668:Metallothionein / Q000378:metabolism*; D012474:Salmon
chemical_list: D008667:Metalloproteins; D003300:Copper; D008668:Metallothionein