title: Structure-activity relationships of C21 steroids in an in vitro oocyte maturation bioassay in rainbow trout, Salmo gairdneri.
abstract: Rainbow trout, Salmo gairdneri, oocytes were used in an in vitro bioassay to test for the potency of C21 steroids in inducing final maturation. A wide range of steroids was used and most of the assays were replicated at least 3 times and up to 10 times with the most effective steroids. 17 alpha,20 beta-Dihydroxy-4-pregnen-3-one (17,20 beta-P), which has been identified as the natural maturation-inducing steroid in Salmoniformes, was used as the reference steroid. Four steroids, 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one; 3 alpha,17 alpha,20 beta-trihydroxy-5 alpha-pregnane; 3 beta,17 alpha,20 beta-trihydroxy-5 alpha-pregnane; and 3 alpha,17 alpha,20 beta,21-tetrahydroxy-5 alpha-pregnane were found to be equipotent with 17,20 beta-P. Analysis of the structure-activity relationships indicated that, for maximum biological activity, steroids must have a planar nucleus (as in delta 4 and 5 alpha-reduced steroids), a hydroxyl or keto group at position 3, and hydroxyl groups at positions 17 and 20 beta. Steroids with delta 5 or 5 beta-reduced conformations and/or hydroxyl or keto groups at position 11 had a much reduced biological activity.
authors.affiliation: Universidade do Algarve, Faro, Portugal.
authors.forename: A V
authors.initials: AV
authors.lastname: Canario
authors.forename: A P
authors.initials: AP
authors.lastname: Scott
mesh_terms: D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D009865:Oocytes / Q000187:drug effects*; D011276:Pregnanediol / Q000031:analogs & derivatives* / Q000494:pharmacology; D011282:Pregnenediones / Q000494:pharmacology*; D012487:Salmonidae / Q000502:physiology*; D013329:Structure-Activity Relationship; D014337:Trout / Q000502:physiology*
chemical_list: D011282:Pregnenediones; D011276:Pregnanediol