GENDER AND SEASONAL DIFFERENCES IN THE ADRENOCORTICAL-RESPONSE TO ACTH CHALLENGE IN AN ARCTIC PASSERINE, ZONOTRICHIA LEUCOPHRYS GAMBELII
GENDER AND SEASONAL DIFFERENCES IN THE ADRENOCORTICAL-RESPONSE TO ACTH CHALLENGE IN AN ARCTIC PASSERINE, ZONOTRICHIA LEUCOPHRYS GAMBELII
复制标题
DOI：
10.1006/gcen.1994.1057
复制
发表时间：
1994-04-01
影响因子：
2.7
通讯作者：
WINGFIELD, JC
中科院分区：
文献类型：
--
作者：
ASTHEIMER, LB;BUTTEMER, WA;WINGFIELD, JC
我们使用标准化的捕获应激方案评估了Gee-living甘贝尔白冠麻雀（Zonotrichia leucophrys gambelii）的肾上腺皮质对急性应激的反应，在一个小时的圈养过程中（1,5,10,30和60分钟），取了5个连续的血液样本（70 μ l）来测量血浆皮质酮(B)。在野外捕获的鸟类中，在繁殖季节，雄性血浆B水平比捕获压力下的雌性高出2 - 4倍，但在冬季（非繁殖）没有差异。我们通过对繁殖和非繁殖麻雀进行地塞米松（DEX）抑制试验来研究这种模式的基础。该试验包括皮下DEX（一种强效的合成糖皮质激素）植入预处理，颈内注射促肾上腺皮质激素（ACTH）或生理盐水，然后收集一系列血液样本，评估2小时内的血浆B水平。注射促肾上腺皮质激素（ACTH）后，雄性和雌性的B水平均升高，非繁殖期的B水平始终低于繁殖期的B水平。除繁殖雄性外，所有经dex处理、注射了盐水的鸟类在激射后的整个2小时内都保持低B水平。这表明DEX对下丘脑-垂体-肾上腺轴有有效的负反馈，从而抑制内源性B的分泌。在繁殖雄性中糖皮质激素反馈抑制的明显减少可能与肾上腺对生殖行为的影响解偶联有关。(C) 1994学术出版社，Inc.
We evaluated the adrenocortical response to acute stress in Gee-living Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) using a standardized capture stress protocol in which five serial blood samples (70 mu l) were taken for measurement of plasma corticosterone (B) over the course of an hour of captivity (at 1, 5, 10, 30, and 60 min). In field-captured birds, male plasma B levels rose two to four times higher than those of females under capture stress during the breeding season, but were no different during winter (nonbreeding). We investigated the basis of this pattern by conducting dexamethasone (DEX) suppression tests on breeding and nonbreeding sparrows of both genders. This test involves pretreatment with subcutaneous DEX implants (a potent synthetic glucocorticoid) and challenge with intrajugular injections of either corticotropin (ACTH) or saline, followed by collection of a series of blood samples for evaluation of plasma B levels over a 2-hr period. ACTH injections in DEX-treated birds resulted in elevated B in both genders, with nonbreeding B profiles consistently lower than those of breeding birds. All DEX-treated, saline-injected birds, except breeding males, maintained low B levels for the entire 2-hr post-challenge period. This result indicates effective negative feedback by DEX on the hypothalamic-pituitary-adrenal axis, thus inhibiting endogenous B secretion. The apparent reduction in glucocorticoid feedback inhibition in breeding males may be related to an uncoupling of adrenal effects on reproductive behavior. (C) 1994 Academic Press, Inc.