title: Nuclear binding of cortisol in intestinal mucosa and liver of a teleost fish (Salmo gairdnerii irideus).
abstract: Nuclear binding of corticosteroids in fish tissues was investigated in two target organs of the trout Salmo gairdnerii irideus: the liver and the intestinal mucosa. Incubation of intact nuclei with [3H]-cortisol or [3H]-dexamethasone failed to demonstrate high-affinity binding of these steroids to proteins. Exchange assay of [3H]-cortisol in high-salt nuclear extracts indicated an association constant Ka = 1.9 X 10(4) M-1 for intestinal mucosa and 2.1 X 10(4) M-1 for liver. In sea water-adapted trout, the association constant remained the same as in fresh water. These results extend previous observations obtained on the cytosol which showed that no high-affinity receptors could be disclosed in fish tissues using these two corticosteroids.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D003907:Dexamethasone / Q000378:metabolism; D006854:Hydrocortisone / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D014337:Trout
chemical_list: D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; C029360:hydrocortisone receptor; D003907:Dexamethasone; D006854:Hydrocortisone