Correlation between binding affinities of C21 steroids for the maturation-inducing steroid membrane receptor in spotted seatrout ovaries and their agonist and antagonist activities in an oocyte maturation bioassay.
Correlation between binding affinities of C21 steroids for the maturation-inducing steroid membrane receptor in spotted seatrout ovaries and their agonist and antagonist activities in an oocyte maturation bioassay.
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C21 类固醇与斑鳟卵巢中成熟诱导类固醇膜受体的结合亲和力与其在卵母细胞成熟生物测定中的激动剂和拮抗剂活性之间的相关性。
DOI：
10.1095/biolreprod57.5.999
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发表时间：
1997
影响因子：
3.6
通讯作者：
Das,S
中科院分区：
文献类型：
--
作者：
Thomas,P;Das,S
将类固醇对斑点鳟鱼（Cynoscion nebulosus）卵巢中成熟诱导类固醇（MIS）质膜受体的相对结合亲和力与其在体外诱导斑鳟卵母细胞最终卵母细胞成熟（FOM）的相对效力进行比较。 MIS 受体对 11 位缺乏酮或羟基 (OH) 的 C21 类固醇（孕烯）具有特异性。在孕酮和孕烯醇酮衍生物的 17、20 或 21 位添加单个 OH 基团以及在 17、20 和 17、21 位添加两个 OH 会降低结合亲和力。相反，201 和 21 位的 OH 组合增加了亲和力，并且在 17、20β 和 21 位的三个 OH（17,20β,21-三羟基-4-pregnen-3-one；20,B-S）（该物种中的天然 MIS）处观察到对孕酮衍生物的最大结合亲和力。生泡破裂 (GVBD) 生物测定表明，体外暴露于 290 nM 20β-S 或 17,20β-二羟基-4-pregnen-3-one (17,20β-P) 1 分钟足以诱导鳟鱼和密切相关物种大西洋黄花鱼 (Micropogonias undulatus) 的卵泡封闭卵母细胞最终成熟，而其他类固醇经测试无效。尽管两种类固醇的卵泡摄取相似，但在较低类固醇浓度（5 nM-100 nM）下暴露 1 分钟后，20β-S 比 17,20β-P 更能诱导 GVBD。将鳟鱼卵母细胞与其他类固醇共孵育 1 分钟，其浓度能够从其受体上取代超过 80% 的结合 20β-S，有效阻断 5 nM 20β-S 对 GVBD 的诱导。类固醇对 MIS 受体的结合亲和力通常与其在 GVBD 生物测定中的激动剂或拮抗剂活性相关。这些发现有力地支持了斑点鳟鱼中 MIS 诱导 FOM 仅通过卵巢质膜 20²-S 受体介导的概念。
The relative binding affinities of steroids for the maturationinducing steroid (MIS) plasma membrane receptor in spotted seatrout (Cynoscion nebulosus) ovaries were compared to their relative potencies in inducing final oocyte maturation (FOM) of seatrout oocytes in vitro. The MIS receptor is specific for C21 steroids (pregnenes) lacking ketone or hydroxyl (OH) groups at the 11 position. The addition of single OH groups at the 17, 20, or 21 positions and two OHs at the 17, 20 and at the 17, 21 positions of both progesterone and pregnenolone derivatives decreased binding affinity. In contrast, the combination of OH at the 201 and 21 positions increased affinity, and greatest binding affinity for a progesterone derivative was observed with three OHs at positions 17, 20β, and 21 (17,20β,21-trihydroxy-4-pregnen- 3-one; 20,B-S), the natural MIS in this species. Germinal vesicle breakdown (GVBD) bioassays showed that 1-min exposure to 290 nM 20β-S or 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) in vitro was sufficient to induce final maturation of follicle-enclosed oocytes of seatrout and a closely related species, Atlantic croaker (Micropogonias undulatus), whereas the other steroids tested were ineffective. 20β-S was more potent than 17,20β-P in inducing GVBD after 1-min exposure at lower steroid concentrations (5 nM-100 nM), even though the follicular uptake of the two steroids was similar. Coincubation of seatrout oocytes for 1 min with other steroids at concentrations capable of displacing more than 80% of the bound 20β-S from its receptor effectively blocked the induction of GVBD by 5 nM 20β-S. The binding affinities of steroids for the MIS receptor correlated in general with either their agonist or their antagonist activities in the GVBD bioassays. These findings strongly support the concept that induction of FOM by the MIS in spotted seatrout is mediated solely through the ovarian plasma membrane 20²-S receptor.