Steroidogenic Pathway to Estradiol-17β Synthesis in the Ovarian Follicles of the Protogynous Wrasse, Pseudolabrus sieboldi
Steroidogenic Pathway to Estradiol-17β Synthesis in the Ovarian Follicles of the Protogynous Wrasse, Pseudolabrus sieboldi
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原生濑鱼 (Pseudolabrus sieboldi) 卵巢卵泡中雌二醇-17β 合成的类固醇生成途径
DOI：
10.2108/zsj.18.937
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发表时间：
2001
期刊：
影响因子：
9.2
通讯作者：
M. Matsuyama
中科院分区：
文献类型：
--
作者：
K. Ohta;Takayuki Mine;A. Yamaguchi;M. Matsuyama
摘要拟隆头鱼是一种昼夜节律的雌性先雌先熟鱼类，在产卵季节雌性每天产卵。研究了竹叶隆头鱼卵黄发生卵泡中雌二醇-17 β（E2）的合成途径。我们在体外培养卵泡与放射性标记的类固醇前体，并测量血清类固醇水平，使用微量滴定板酶联免疫吸附测定（ELISA）。建立了雌酮（E1）和睾酮（T）的ELISA。实验表明，E2是由双烯醇酮经17-羟基双烯醇酮、脱氢表雄酮、雄烯二酮和E1合成的。T不产生任何放射性标记的前体，和外源性T没有转化为E2。在产卵季节，血清中的E2和E1水平表现出相似的模式，与高水平的昼夜节律在03：00小时与活跃的卵巢卵黄发生卵泡。与此相反，血清T水平是恒定的，并且与E2和E1水平相比相对较低。这些结果表明，E2是通过E1合成的，而不是T，在卵泡中，并表明在血液中检测到的T可能来自卵泡外组织。
Abstract The bambooleaf wrasse, Pseudolabrus sieboldi, is a diandric protogynous fish with a diurnal rhythm of ovarian development, and females spawn daily during the spawning season. This study investigated the steroidogenic pathway for estradiol-17β (E2) biosynthesis in vitellogenic ovarian follicles of the bambooleaf wrasse. We incubated follicles in vitro with radioactively labeled steroid precursors, and measured serum steroid levels using microtiter plate enzyme-linked immunosorbent assays (ELISAs). ELISAs for estrone (E1) and testosterone (T) were developed. The experiments showed that E2 was synthesized from pregnenolone via 17-hydroxypregnenolone, dehydroepiandrosterone, androstenedione, and E1. T was not produced from any radiolabeled precursors, and exogenous T was not converted to E2. During the spawning season, serum levels of E2 and E1 showed similar patterns, with a diurnal rhythm of high levels at 03:00 hr associated with active ovarian vitellogenic follicles. In contrast, serum T levels were constant and relatively low compared to levels of E2 and E1. These results indicate that E2 is synthesized via E1, rather than T, in the ovarian follicles, and suggest that T detected in the blood is likely derived from extra-follicular tissues.