Canario A V, Scott A P
Universidade do Algarve, Faro, Portugal.
Gen Comp Endocrinol. 1988 Aug;71(2):338-48. doi: 10.1016/0016-6480(88)90262-6.
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.
虹鳟（Salmo gairdneri）的卵母细胞被用于一项体外生物测定，以测试C21类固醇诱导最终成熟的效力。使用了多种类固醇，并且大多数测定至少重复3次，对于最有效的类固醇重复多达10次。已被确定为鲑形目天然成熟诱导类固醇的17α,20β - 二羟基 - 4 - 孕烯 - 3 - 酮（17,20β - P）被用作参考类固醇。发现四种类固醇，17α,20β,21 - 三羟基 - 4 - 孕烯 - 3 - 酮；3α,17α,20β - 三羟基 - 5α - 孕烷；3β,17α,20β - 三羟基 - 5α - 孕烷；以及3α,17α,20β,21 - 四羟基 - 5α - 孕烷与17,20β - P等效。结构 - 活性关系分析表明，为了获得最大生物活性，类固醇必须具有平面核（如在Δ4和5α - 还原类固醇中），在3位有一个羟基或酮基，以及在17位和20β位有羟基。具有Δ5或5β - 还原构象和/或在11位有羟基或酮基的类固醇生物活性大大降低。
