title: Differences in concentrations of plasma cortisol in the trout and the eel following adaptation to black or white backgrounds.
abstract: When rainbow trout (Salmo gairdneri) and eels (Anguilla anguilla) were kept in black tanks for 3-4 weeks, their plasma cortisol titres were about fourfold higher tha in fish kept in white tanks. In trout, the difference was apparent only under a long photoperiod of 16 h light: 8 h darkness, but in eels the difference was clear under both a long or short photoperiod (9.5 h light: 14.5 darkness). It is suggested that the increase in plasma cortisol seen in black-adapted fish is dependent on either ACTH or MSH secreted by the pars intermedia melanotrophs. No difference was seen in the total cortisol-binding capacity of the plasma nor in interrenal histology in trout from black or white backgrounds.
mesh_terms: D000221:Adaptation, Ocular; D000818:Animals; D004524:Eels / Q000097:blood*; D006854:Hydrocortisone / Q000097:blood*; D007401:Interrenal Gland / Q000648:ultrastructure; D008027:Light; D008547:Melanophores / Q000502:physiology; D010507:Periodicity; D012487:Salmonidae / Q000097:blood*; D014337:Trout / Q000097:blood*
chemical_list: D006854:Hydrocortisone