Data to support Seasonal blubber steroid profiles of free-ranging bottlenose dolphins (Tursiops truncatus)

Liquid chromatography tandem mass spectrometry allows for the measurement of
steroid hormone suites in the blubber of marine mammals. By combining this technology
with remote biopsy collection, endocrine profiles can be assessed, allowing for studies
of hormonal profile variation over time. In this study, we explored associations among
different steroidogenic pathways and seasonal differences in blubber hormone profiles of
free-ranging common bottlenose dolphins along the coast of South Carolina, USA. We found
that male dolphins experience a peak in testosterone, androstenedione, progesterone, and
17-hydroxyprogesterone in the spring, likely related to an upregulation of the androgen
steroidogenic pathway during mating season. We also observed increased cortisol
concentrations not related to blubber lipid percentages during summer compared to other
months. Though the sample size of females was insufficient to describe female seasonal
patterns, there was an increase in androstenedione among females with elevated
progesterone concentrations indicative of pregnancy, highlighting another potential
endocrine marker for pregnancy in free-ranging dolphins. This work emphasizes the
importance of selecting the appropriate season for studies on endocrine status to
effectively uncover physiological variation or disruption in free-ranging
cetaceans.

液相色谱-串联质谱法（Liquid chromatography tandem mass spectrometry）可用于测定海洋哺乳动物鲸脂中的类固醇激素谱。将该技术与远程活检采样相结合，即可实现内分泌特征谱的分析，从而开展激素特征随时间变化的相关研究。本研究针对美国南卡罗来纳州沿岸自由栖息的普通宽吻海豚（common bottlenose dolphins），探究了不同类固醇生成通路与鲸脂激素特征谱季节差异之间的关联。研究结果显示，雄性海豚体内的睾酮、雄烯二酮、孕酮及17-羟孕酮在春季达到峰值，这一现象大概率与交配季雄激素类类固醇生成通路的上调调控有关。此外，本研究还观察到，相较于其他月份，夏季的皮质醇浓度显著升高，且该变化与鲸脂脂质占比无明显关联。尽管雌性个体的样本量不足，无法完整阐明其季节变化规律，但在孕酮浓度升高（提示妊娠）的雌性海豚中，雄烯二酮水平同样有所上升，这为野生海豚的妊娠内分泌标志物筛查提供了又一潜在靶点。本研究凸显了在野生鲸类内分泌状态研究中选择恰当采样季节的重要性，可有效揭示其生理变化或紊乱机制。