Jessop Tim S, Knapp Rosemary, Whittier Joan M, Limpus Col J
Department of Zoology, University of Oklahoma, Norman, Oklahoma 73019, USA.
Gen Comp Endocrinol. 2002 Mar;126(1):59-67. doi: 10.1006/gcen.2001.7769.
During reproduction, male vertebrates may exhibit a continuum of interactions between sex and adrenal steroids during stressful events, the outcome of which may be important in either reducing or promoting male reproductive success. We studied adult male green turtles (Chelonia mydas) to examine if they altered plasma corticosterone (CORT) and androgen levels in response to a standardized capture/restraint stressor as potential mechanisms to maintain reproductive activity during stressful events. At the population level, we found that migrant breeding males had a significantly smaller CORT response to the capture/restraint stressor compared to nonbreeding males and that this decreased response coincided with the generally poorer body condition of migrant breeders. In contrast, plasma androgen levels decreased significantly in response to the capture/restraint stressor in migrant breeding males, but not in nonbreeding and pre-migrant breeding males. For individual migrant breeding males, the magnitude of their CORT and androgen responses to the capture/restraint stressor was highly correlated with their body condition and body length, respectively. Our results demonstrate that male green turtles exhibit complex interactions in their endocrine responses to a capture/restraint stressor and that variation in these interactions is associated with differences in males' reproductive, energetic, and physical state. We hypothesize that interplay between physical status and plasma hormone responses to stressors could have important consequences for male green turtle reproduction.
在繁殖过程中，雄性脊椎动物在应激事件期间可能会表现出性激素与肾上腺类固醇之间的一系列相互作用，其结果对于降低或促进雄性繁殖成功率可能很重要。我们研究了成年雄性绿海龟（蠵龟），以检验它们是否会因标准化的捕捉/束缚应激源而改变血浆皮质酮（CORT）和雄激素水平，这是在应激事件期间维持繁殖活动的潜在机制。在种群水平上，我们发现，与非繁殖雄性相比，洄游繁殖雄性对捕捉/束缚应激源的CORT反应明显较小，且这种反应的降低与洄游繁殖者总体较差的身体状况相一致。相比之下，洄游繁殖雄性的血浆雄激素水平在对捕捉/束缚应激源作出反应时显著下降，但非繁殖雄性和洄游前繁殖雄性则不然。对于个体洄游繁殖雄性来说，它们对捕捉/束缚应激源的CORT和雄激素反应的强度分别与它们的身体状况和体长高度相关。我们的结果表明，雄性绿海龟在对捕捉/束缚应激源的内分泌反应中表现出复杂的相互作用，且这些相互作用的变化与雄性的繁殖、能量和身体状态差异有关。我们推测，身体状态与血浆激素对应激源的反应之间的相互作用可能对雄性绿海龟的繁殖产生重要影响。
