Reproductive Steroid Hormone Patterns in Baleen of Two Pregnant Humpback Whales ( Megaptera novaeangliae )
Reproductive Steroid Hormone Patterns in Baleen of Two Pregnant Humpback Whales ( Megaptera novaeangliae )
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两只怀孕座头鲸鲸须的生殖类固醇激素模式（Megaptera novaeangliae）
DOI：
10.1093/icb/icac070
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发表时间：
2022
影响因子：
2.6
通讯作者：
Buck, C Loren
中科院分区：
文献类型：
--
作者：
Lowe, Carley L;Hunt, Kathleen E;Neilson, Janet L;Gabriele, Christine M;Teerlink, Suzie S;Buck, C Loren
由于缺乏来自个体的重复样本，对神秘菌生殖生理学的了解已经放缓。对座头鲸须的分析可以使个体在死亡前3-5年进行回顾性激素分析。利用这种方法，我们研究了两只已知生殖史的雌性座头鲸（Megaptera novaeangliae）在怀孕和未怀孕期间与生殖和交配有关的四种类固醇激素的差异。皮质醇、皮质酮、睾酮和雌二醇浓度通过酶免疫分析法测定，每隔2cm使用每个须鲸板的亚样本。怀孕期间的皮质醇或皮质酮与未怀孕期间（产犊间隔）相比没有显著差异，但两只鲸鱼的平均糖皮质激素浓度存在显著差异，幼鲸总体上显示出更高的值。对于睾丸激素，年轻女性的水平在一次怀孕中分娩时达到峰值，但在非怀孕期间也有峰值。年长的雌性有三个大的睾丸激素峰值，其中一个与分娩有关。雌二醇在两只鲸鱼体内波动很大，但在非怀孕期间的浓度通常低于怀孕期间。雌二醇在每次怀孕前都有高峰，可能与排卵同时出现，高峰与分娩月份同时出现。雌二醇和睾酮都可以用于确定排卵或即将分娩。利用鲸须研究回顾性类固醇激素谱可用于阐明妊娠期间生理变化的长期模式。对两只怀孕的座头鲸的案例研究，在鲸须中分析了它们的激素，这可能会说明座头鲸何时排卵、怀孕和分娩。这些生理指标有助于准确的种群增长评估和物种保护。这项研究表明，鲸须激素分析可以成为了解鲸鱼生殖生理的有用工具。
Understanding reproductive physiology in mysticetes has been slowed by the lack of repeated samples from individuals. Analysis of humpback whale baleen enables retrospective hormone analysis within individuals dating back 3–5 years before death. Using this method, we investigated differences in four steroid hormones involved in reproduction and mating during confirmed pregnant and non-pregnant periods in two female humpback whales (Megaptera novaeangliae) with known reproductive histories based on sightings and necropsy data. Cortisol, corticosterone, testosterone, and estradiol concentrations were determined via enzyme immunoassay using subsamples of each baleen plate at 2 cm intervals. There were no significant differences in cortisol or corticosterone during pregnancy when compared to non-pregnancy (inter-calving interval), but there were significant differences between the two whales in average glucocorticoid concentrations, with the younger whale showing higher values overall. For testosterone, levels for the younger female peaked at parturition in one pregnancy, but also had spikes during non-pregnancy. The older female had three large spikes in testosterone, one of which was associated with parturition. Estradiol had large fluctuations in both whales but had generally lower concentrations during non-pregnancy than during pregnancy. There were peaks in estradiol before each pregnancy, possibly coinciding with ovulation, and peaks coinciding with the month of parturition. Both estradiol and testosterone could be useful for determining ovulation or impending birth. Using baleen to investigate retrospective steroid hormone profiles can be used for elucidating long-term patterns of physiological change during gestation.Lay summaryCase studies of two pregnant humpback whales whose hormones were analyzed in baleen may illuminate when humpback whales ovulate, gestate, and give birth. These physiological metrics could assist in accurate population growth assessments and conservation of the species. This study shows that baleen hormone analysis can be a useful tool for understanding whale reproductive physiology.