Hunt Kathleen E, Rolland Rosalind M, Kraus Scott D, Wasser Samuel K
Center for Conservation Biology, Department of Biology, University of Washington, Seattle, WA 98195-1800, USA.
Gen Comp Endocrinol. 2006 Sep 1;148(2):260-72. doi: 10.1016/j.ygcen.2006.03.012. Epub 2006 May 2.
Very little is known about the endocrinology of the baleen whales. The highly endangered North Atlantic right whale (NARW; Eubalaena glacialis) is a good model species, because most NARW individuals are photo-identified with known histories. We used an 125I corticosterone assay, shown to reliably measure cortisol metabolites, to determine glucocorticoid metabolite concentrations in 177 NARW fecal samples collected between 1999-2004 in the Bay of Fundy, Canada. Fecal glucocorticoid metabolite concentrations varied significantly with sex and reproductive category, being highest in pregnant females (mean +/-SE: 238.14+/-74.37 ng/g) and mature males (71.6+/-11.36), intermediate in lactating females (39.33+/-5.82), and lower in non-reproducing females (23.11+/-4.25) and immature males (34.33+/-5.01) and females (14.0+/-0.41). One case also suggests that glucocorticoids rise markedly in response to severe entanglement in fishing lines. Whales with fecal glucocorticoid content over 100 ng/g (termed "high-cort" samples) were rare, and included most pregnant females, some mature males, a fatally entangled whale, and several very young animals. Glucocorticoid concentrations were highly correlated with androgen concentrations in males and pregnant females. We analyzed the elution profiles of glucocorticoid and androgen metabolites in 13 samples with high-performance liquid chromatography (HPLC) to determine the extent to which androgen metabolites cross-react with our glucocorticoid assay. Males, pregnant females, non-pregnant females, and "high-cort" whales each had distinctly different immunoreactive HPLC profiles of glucocorticoid and androgen metabolites. A major glucocorticoid metabolite was prominent in all "high-cort" whales including the fatally entangled whale. The major fecal androgen was not testosterone but was instead a more nonpolar steroid (possibly dihydrotestosterone), which may be diagnostic of males. Androgen metabolites showed only minor cross-reactivity to our glucocorticoid assay, having a slight influence on glucocorticoid results in particular individuals. We conclude that fecal glucocorticoid analysis appears to be a useful measure of adrenal activity and reproductive condition for NARW.
关于须鲸的内分泌学，人们所知甚少。极度濒危的北大西洋露脊鲸（NARW；Eubalaena glacialis）是一个很好的模式物种，因为大多数NARW个体都通过照片识别且具有已知的生活史。我们使用一种已证明能可靠测量皮质醇代谢物的125I皮质酮测定法，来测定1999年至2004年间在加拿大芬迪湾采集的177份NARW粪便样本中的糖皮质激素代谢物浓度。粪便糖皮质激素代谢物浓度因性别和生殖类别而有显著差异，在怀孕雌性中最高（平均值±标准误：238.14±74.37 ng/g），在成年雄性中次之（71.6±11.36），在哺乳雌性中处于中等水平（39.33±5.82），在非繁殖雌性（23.11±4.25）、未成年雄性（34.33±5.01）和未成年雌性（14.0±0.41）中较低。一个案例还表明，糖皮质激素会因严重被钓线缠住而显著升高。粪便糖皮质激素含量超过100 ng/g的鲸鱼（称为“高皮质”样本）很罕见，包括大多数怀孕雌性、一些成年雄性、一头被致命缠住的鲸鱼以及几只非常年幼的动物。糖皮质激素浓度与雄性和怀孕雌性中的雄激素浓度高度相关。我们用高效液相色谱法（HPLC）分析了13个样本中糖皮质激素和雄激素代谢物的洗脱曲线，以确定雄激素代谢物与我们的糖皮质激素测定法发生交叉反应的程度。雄性、怀孕雌性、非怀孕雌性和“高皮质”鲸鱼各自具有明显不同的糖皮质激素和雄激素代谢物免疫反应性HPLC曲线。一种主要的糖皮质激素代谢物在所有“高皮质”鲸鱼中都很突出，包括那头被致命缠住的鲸鱼。主要的粪便雄激素不是睾酮，而是一种极性更小的类固醇（可能是二氢睾酮），这可能是雄性的诊断指标。雄激素代谢物对我们的糖皮质激素测定法仅表现出轻微的交叉反应，对特定个体的糖皮质激素结果有轻微影响。我们得出结论，粪便糖皮质激素分析似乎是评估NARW肾上腺活动和生殖状况的一种有用方法。
