Involvement of cortisol and metallothionein-like proteins in the physiological responses of tilapia ( Oreochromis mossambicus) to sublethal cadmium stress

• Published in: Aquatic toxicology 1990, Vol.16 (4), p.257-269
• Main Authors: Fu, H., Steinebach, O.M., van den Hamer, C.J.A., Balm, P.H.M., Lock, R.A.C.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Cadmium; Chloride cells; Cortisol; Freshwater fish; Fundamental and applied biological sciences. Psychology; Ion balance; Metallothioneins; Oreochromis mossambicus
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/0166-445X(90)90040-V

Exposure of freshwater tilapia to a sublethal cadmium concentration in the water (10 μg Cd/l) induced a rapid elevation (within 1 h) of plasma cortisol levels. Concentrations remained increased for at least 4 days during which time hypocalcemia, hyponatremia and hyperglycemia were observed; concurrently the opercular chloride cell density doubled. After this time, cortisol levels gradually decreased, plasma cadmium, natrium and glucose returned to (near) normal levels while a concomitant rise in the metallothionein-like protein content of gill, kidney and liver was observed. We conclude that, in tilapia, cortisol, by initiating physiological responses and via possible synergism with other hormones like prolactin, enables the fish to counter-act the adverse effects of Cd. This hormonal response apparently forms an intrinsic part of a general adaptation response of fish to sublethal Cd-stress.