title: An investigation of an estrogen-binding component in the liver and plasma of brook char, Salvelinus fontinalis.
abstract: 1. Estrogen-binding activity was investigated in liver nuclear and cytosolic preparations of sexually mature female brook char, Salvelinus fontinalis. Nuclear salt extracts of estrogen-injected fish were found to contain high affinity binding sites (Kd = 1.6 nM, capacity = 2.8 fM/ug DNA). 2. Low levels of high-affinity specific binding activity were found in the cytosol of both injected and untreated fish (Kd = 7.5 nM, capacity = 16.1 fM/mg protein). 3. Binding sites in both preparations were specific for estrogens with no significant competition by 5 alpha-dihydrotestosterone, progesterone, or cortisone. 4. A plasma-binder was found to have distinctive differences with regard to structural specificity compared to the estrogen-binding component in liver. It was found to have no affinity for diethylstilbestrol while having some affinity for both 5 alpha-dihydrotestosterone and progesterone. 5. The brook char liver estrogen-binding component was observed to have characteristics in common with estrogen receptors found in other vertebrates.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000097:blood / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005399:Fishes / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D011960:Receptors, Estrogen; C010140:estrophilin; D004958:Estradiol