Effects of copper on cortisol receptor and metallothionein expression in gills of Oncorhynchus mykiss

• Published in: Aquatic toxicology 2000-11, Vol.51 (1), p.45-54
• Main Authors: Chao Dang, Zhi, Flik, Gert, Ducouret, Bernadette, Hogstrand, Christer, E. Wendelaar Bonga, Sjoerd, A.C. Lock, Robert
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Chloride cell; Copper - toxicity; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on vertebrates; Enzyme Induction - drug effects; Epithelial Cells - drug effects; Epithelial Cells - enzymology; Epithelial Cells - metabolism; Fish g̱ills; Freshwater; Fundamental and applied biological sciences. Psychology; Gills - cytology; Gills - drug effects; Gills - enzymology; Glucocorticoid receptor; Hydrocortisone - blood; Hydrocortisone - metabolism; hydrocortisone receptors; Immunocytochemistry; Immunohistochemistry; Metallothionein; Metallothionein - biosynthesis; Microscopy, Confocal; Oncorhynchus mykiss; Oncorhynchus mykiss - physiology; Receptors, Glucocorticoid - drug effects; Receptors, Glucocorticoid - metabolism; Sodium-Potassium-Exchanging ATPase - biosynthesis
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/S0166-445X(00)00102-8

Effects of waterborne Cu (2.4 μM) on the expression of glucocorticoid receptor (GR) and metallothionein (MT) in the branchial epithelium of freshwater rainbow trout (Oncorhynchus mykiss) was studied by immunocytochemistry. After 5 days of Cu exposure, the number of GR-immunoreactive (GR-ir) cells in the gill epithelium had decreased, whereas the number of MT-ir cells had increased. Localization of GR in chloride cells was achieved by double staining for Na +/K +-ATPase; other cell types were identified on the basis of their topology. GRs were present in the chloride cells in both the filaments and lamellae, in respiratory cells in the lamellae, in pavement cells, basal layer cells and undifferentiated cells in the filaments. Co-localization of Na +/K +-ATPase and MT revealed chat MT was expressed in chloride cells, both in filaments and lamellae. Occasionally, MT immunoreactivity was found in pavement cells and in undifferentiated cells. By double staining for Na +/K +-ATPase and GR, for Na +/K +-ATPase and MT and for GR and MT, we can conclude that after 5 days of Cu stress there are chloride cells that express GR and MT, GR or MT alone or neither of the two proteins. This apparent functional heterogeneity of branchial chloride cells may reflect a limited window when chloride cell subpopulations show an adaptive response to Cu.