Institute of Integrative and Comparative Biology, University of Leeds, Leeds LS2 9JT, UK.
Gen Comp Endocrinol. 2010 Aug 1;168(1):8-13. doi: 10.1016/j.ygcen.2010.03.011. Epub 2010 Mar 21.
While the role of corticosterone in mediating the response of birds to acute stress is well established, it has recently been proposed that a decrease in prolactin levels following stress may complement corticosterone in redirecting resources away from breeding activities and towards behaviors promoting immediate survival. Here, for the first time, we detail changes in the prolactin stress response of birds throughout the breeding cycle. We then discuss the modulation of the corticosterone and prolactin stress responses over successive stages of breeding, differing in reproductive value and parental effort. In a long-lived Procellariiform seabird, the Manx shearwater Puffinus puffinus, we found that prolactin levels decreased in response to acute stress during incubation and mid chick-rearing but increased in response to stress during late chick-rearing and in non parenting birds, a pattern similar to that previously described for mammals. The high corticosterone stress response in pre-breeders was consistent with predictions based on reproductive value, but a similar response during late chick-rearing was not. This probably reflected foraging effort and a heightened importance of the parents' own nutritional status at this stage of the season, in advance of post-breeding migration. We also found that baseline prolactin levels were maintained at high levels during chick-rearing and were only slightly lower during late chick-rearing and in failed breeders and non-breeders. These data suggest that prolactin may play a role in nestling care long beyond the brooding phase, that this is not due to birds spending long periods away from the colony and that prolactin secretion may be necessary for nest-guarding behavior.
虽然皮质酮在介导鸟类对急性应激的反应中的作用已得到充分证实，但最近有人提出，应激后催乳素水平的下降可能与皮质酮一起，将资源从繁殖活动重新分配到促进即时生存的行为上。在这里，我们首次详细描述了鸟类在繁殖周期中催乳素应激反应的变化。然后，我们讨论了在繁殖的连续阶段中，皮质酮和催乳素应激反应的调制，这些阶段在生殖价值和亲代努力方面存在差异。在一种长寿的磷虾类海鸟——凤头燕鸥（Puffinus puffinus）中，我们发现催乳素水平在孵化和育雏中期对急性应激的反应下降，但在育雏后期和非亲鸟中对应激的反应增加，这种模式类似于先前描述的哺乳动物模式。在繁殖前的鸟类中，高皮质酮应激反应与基于生殖价值的预测一致，但在育雏后期没有类似的反应。这可能反映了在这个季节的后期，觅食努力和父母自身营养状况的重要性增加，以应对繁殖后的迁徙。我们还发现，在育雏期间，催乳素的基础水平保持在高水平，只有在育雏后期和繁殖失败的鸟类和非繁殖鸟类中略低。这些数据表明，催乳素可能在育雏期之后很长一段时间内对雏鸟的照顾发挥作用，这并不是因为鸟类长时间远离巢穴，而且催乳素的分泌可能是巢守卫行为所必需的。
