Gonad histology and plasma steroid profiles in wild New Zealand freshwater eels (Anguilla dieffenbachii and A-australis) before and at the onset of the natural spawning migration.: I.: Females
Gonad histology and plasma steroid profiles in wild New Zealand freshwater eels (Anguilla dieffenbachii and A-australis) before and at the onset of the natural spawning migration.: I.: Females
复制标题
DOI：
10.1023/a:1007719414295
复制
发表时间：
1998-12-01
影响因子：
2.9
通讯作者：
Young, G
中科院分区：
文献类型：
--
作者：
Lokman, PM;Vermeulen, GJ;Young, G
为了确定来自野生、非洄游和洄游的新西兰长鳍鳗（Anguilla dieffenbachii）和短鳍鳗（A.捕捞鳗鱼并采集血液和卵巢样本。测定血浆类固醇水平，并与卵巢的发育阶段。非迁移者的卵巢含有卵原细胞和前卵黄发生卵母细胞。在这些组中从未观察到卵黄发生卵母细胞，但在迁移者中非常常见（高达88%的卵母细胞）。两种雄激素（雄烯二酮（AD），睾酮（T））和雌二醇-17 β（E-2）的浓度均高于IRI移民比非移民。在洄游鱼中，短鳍鱼的T水平（2.27 +/- 0.14 ng ml（-1））高于长鳍鱼（0.82 +/- 0.10 ng ml（-1）），而长鳍鱼的E-2水平（平均2.46 ng ml（-1））高于短鳍鱼。非移民的性类固醇水平普遍较低。与此相反，17-羟孕酮的血浆水平显着高于非移民比移民。同样，皮质醇水平较高，在非迁移比迁移短鳍，但不是longfinned，女性。17，20 β-二羟基-4-异戊烯-3-酮（假定的鳗鲡类成熟诱导类固醇）在所有检查动物中均接近最低可检测水平。令人惊讶的是，在移民中发现了非常高水平的11-酮睾酮（KT），长鳍鱼平均接近3 ng ml（-1），短鳍鱼超过20 ng ml（-1）。使用气相色谱-质谱法确认KT和几种5-还原雄激素的身份。KT在女性的功能是未知的，但我们认为，这种类固醇激素可能发挥作用，在准备成熟的动物产卵迁移。
To determine steroid profiles in immature and maturing female eels from the wild, non-migratory and migratory New Zealand longfinned (Anguilla dieffenbachii) and shortfinned (A. australis) eels were caught and blood and ovarian samples collected. Plasma steroid levels were determined and related to the developmental stage of the ovary. Ovaries of non-migrants contained oogonia and previtellogenic oocytes. Vitellogenic oocytes were never observed in these groups, but instead were very common among migrants (up to 88% of oocytes). Concentrations of both androgens (androstenedione (AD), testosterone (T)) and estradiol-17 beta (E-2) were higher iri migrants than in non-migrants. Among migrants, T levels were higher in shortfins (2.27 +/- 0.14 ng ml(-1)) than in longfins (0.82 +/- 0.10 ng ml(-1)), whereas E-2 levels were higher in longfins (mean 2.46 ng ml(-1)) than in shortfins. Levels of sex steroids were generally low in non-migrants. In contrast, plasma levels of 17-hydroxyprogesterone were significantly higher in non-migrants than in migrants. Similarly, cortisol levels were higher in non-migrating than in migrating shortfinned, but not longfinned, females. 17,20 beta-Dihydroxy-4-pregnen-3-one, the putative maturation inducing steroid in anguillids, was near minimum-detectable levels for all animals examined. Surprisingly, very high levels of 11-ketotestosterone (KT) were found in migrants, averaging nearly 3 ng ml(-1) in longfins and over 20 ng ml(-1) in shortfins. The identity of KT and several 5-reduced androgens was confirmed using gas chromatography - mass spectrometry. The function of KT in females is not known, but we suggest that this steroid hormone may play a role in preparing maturing animals for their spawning migration.