Hypothalamic-pituitary-adrenal axis changes allow seasonal modulation of corticosterone in a bird.
Hypothalamic-pituitary-adrenal axis changes allow seasonal modulation of corticosterone in a bird.
复制标题
DOI：
10.1152/ajpregu.1998.274.5.r1338
复制
发表时间：
1998-05
期刊：
影响因子：
--
通讯作者：
L. Romero;K. Soma;J. Wingfield
中科院分区：
文献类型：
--
作者：
L. Romero;K. Soma;J. Wingfield
我们研究了可能的机制，在拉普兰长马刺（Calcarius lapponicus），一个物种的繁殖和蜕皮（精力昂贵的羽毛更换）在阿拉斯加北极地区的季节性压力调制。自由生活的拉普兰长距显示显着减少最大皮质酮释放蜕皮期间相比，繁殖季节，效果失去了圈养鸟类。无论是皮质酮结合蛋白的变化，还是鸟类的整体状况（通过体重和脂肪储存评估），都不能解释不同季节的皮质酮反应。肾上腺不敏感性也不能完全解释最大输出减少，因为外源性ACTH增强蜕皮期间皮质酮的释放。然而，在换羽鸟类外源性ACTH，不能刺激皮质酮应激诱导的水平在繁殖过程中，这意味着减少肾上腺的能力。拉普兰长距垂体似乎对外源性促肾上腺皮质激素释放因子，精氨酸催产素，中催产素（精氨酸加压素和催产素的鸟类等价物）蜕皮期间，这表明，垂体钝皮质酮释放的机制上游。两者合计，这些结果表明，季节性调节皮质酮释放在这个物种是控制在多个网站在下丘脑-垂体-肾上腺轴。
We examined possible mechanisms underlying seasonal stress modulation in Lapland longspurs ( Calcarius lapponicus), a species that breeds and molts (the energetically costly replacement of feathers) in the Alaskan Arctic. Free-living Lapland longspurs show dramatically reduced maximal corticosterone release during molt compared with the breeding season, an effect lost in captive birds. Neither changes in corticosterone binding proteins nor the overall condition of the bird (assessed by weight and fat storage) can explain different seasonal corticosterone responses. Adrenal insensitivity also does not fully explain reduced maximal output because exogenous ACTH enhanced corticosterone release during molt. Exogenous ACTH in molting birds, however, cannot stimulate corticosterone to stress-induced levels during breeding, implying reduced adrenal capacity. Lapland longspur pituitaries appeared to respond to exogenous corticotropin-releasing factor, arginine vasotocin, and mesotocin (the avian equivalents of arginine vasopressin and oxytocin) during molt, suggesting that a mechanism upstream of the pituitary blunts corticosterone release. Taken together, these results indicate that seasonal modulation of corticosterone release in this species is controlled at multiple sites in the hypothalamic-pituitary-adrenal axis.