Hunt Kathleen E, Lysiak Nadine S, Moore Michael, Rolland Rosalind M
Anderson Cabot Center for Ocean Life, New England Aquarium, Central Wharf, New England, Boston, MA 02110, USA.
Anderson Cabot Center for Ocean Life, New England Aquarium, Central Wharf, New England, Boston, MA 02110, USA; Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Gen Comp Endocrinol. 2017 Dec 1;254:50-59. doi: 10.1016/j.ygcen.2017.09.009. Epub 2017 Sep 14.
Research into stress physiology of mysticete whales has been hampered by difficulty in obtaining repeated physiological samples from individuals over time. We investigated whether multi-year longitudinal records of glucocorticoids can be reconstructed from serial sampling along full-length baleen plates (representing ∼10years of baleen growth), using baleen recovered from two female North Atlantic right whales (Eubalaena glacialis) of known reproductive history. Cortisol and corticosterone were quantified with immunoassay of subsamples taken every 4cm (representing ∼60d time intervals) along a full-length baleen plate from each female. In both whales, corticosterone was significantly elevated during known pregnancies (inferred from calf sightings and necropsy data) as compared to intercalving intervals; cortisol was significantly elevated during pregnancies in one female but not the other. Within intercalving intervals, corticosterone was significantly elevated during the first year (lactation year) and/or the second year (post-lactation year) as compared to later years of the intercalving interval, while cortisol showed more variable patterns. Cortisol occasionally showed brief high elevations ("spikes") not paralleled by corticosterone, suggesting that the two glucocorticoids might be differentially responsive to certain stressors. Generally, immunoreactive corticosterone was present in higher concentration in baleen than immunoreactive cortisol; corticosterone:cortisol ratio was usually >4 and was highly variable in both individuals. Further investigation of baleen cortisol and corticosterone profiles could prove fruitful for elucidating long-term, multi-year patterns in stress physiology of large whales, determined retrospectively from stranded or archived specimens.
须鲸应激生理学的研究一直受到阻碍，因为很难随着时间推移从个体身上获取重复的生理样本。我们利用从两只已知繁殖史的北大西洋露脊鲸（Eubalaena glacialis）雌性个体身上获取的鲸须，研究是否可以通过沿着完整的鲸须板进行连续采样（代表约10年的鲸须生长）来重建糖皮质激素的多年纵向记录。对每只雌性鲸鱼的完整鲸须板每隔4厘米（代表约60天的时间间隔）采集的子样本进行免疫分析，定量测定皮质醇和皮质酮。在两只鲸鱼中，与产犊间隔期相比，已知怀孕期（根据幼鲸目击和尸检数据推断）皮质酮显著升高；在一只雌性鲸鱼的怀孕期间皮质醇显著升高，而另一只则没有。在产犊间隔期内，与产犊间隔期的后期年份相比，皮质酮在第一年（哺乳期）和/或第二年（哺乳后期）显著升高，而皮质醇则表现出更多变的模式。皮质醇偶尔会出现短暂的高浓度升高（“峰值”），而皮质酮则没有，这表明这两种糖皮质激素可能对某些应激源有不同的反应。一般来说，鲸须中免疫反应性皮质酮的浓度高于免疫反应性皮质醇；皮质酮与皮质醇的比值通常>4，且在两个个体中都高度可变。对鲸须皮质醇和皮质酮谱的进一步研究可能有助于阐明大型鲸鱼应激生理学的长期多年模式，这些模式可通过搁浅或存档标本进行回顾性确定。
