Pottinger T G, Carrick T R, Hughes S E, Balm P H
Windermere Laboratory, Institute of Freshwater Ecology, Ambleside, Cumbria, United Kingdom.
Gen Comp Endocrinol. 1996 Dec;104(3):284-95. doi: 10.1006/gcen.1996.0173.
Estradiol-17 beta (E), 11-ketotestosterone (KT), and testosterone (T) were administered to immature rainbow and brown trout by implantation of steroid-containing cocoa butter pellets. This procedure elevated the levels of these hormones in the blood of the treated fish and had significant effects on plasma ACTH and cortisol levels in both unstressed and stressed rainbow trout and in stressed brown trout. E treatment significantly elevated resting levels of ACTH and cortisol and KT significantly suppressed resting ACTH levels in rainbow trout, although no effect of KT was noted on baseline cortisol levels. One hour of confinement stress increased ACTH levels in rainbow trout, but less so in T- and KT-implanted fish than in sham-implanted fish. A similar pattern was observed in stress-induced plasma cortisol levels where T and KT treatment of rainbow trout resulted in a more than 50% attenuation of plasma cortisol levels while E implantation significantly increased stress-induced plasma cortisol levels. In brown trout subjected to confinement stress for 96 hr, within 1 hr of the onset of confinement the stress-induced increase in plasma ACTH and plasma cortisol was significantly lower in T- and KT-implanted fish than in sham-implanted controls. However, these differences were not sustained at subsequent sample points during the 96-hr period of continuous confinement. Nonetheless, overall mean ACTH levels for the entire confinement period were significantly enhanced in E-implanted brown trout and significantly reduced in KT-implanted fish. Overall mean cortisol levels were significantly lower in T- and KT-implanted fish. The enhancement of stress responsiveness observed in E-treated immature fish was not observed during confinement stress in untreated mature female trout, with naturally high plasma E levels. However, untreated mature male trout displayed a significantly reduced cortisol response to confinement. It is suggested that gonadal steroids are involved in the regulation of both baseline and stress-induced activity of the pituitary-interrenal axis in salmonid fish.
通过植入含类固醇的可可脂丸，将17β-雌二醇（E）、11-酮睾酮（KT）和睾酮（T）给予未成熟的虹鳟鱼和褐鳟。该程序提高了处理过的鱼血液中这些激素的水平，并且对未受应激和受应激的虹鳟鱼以及受应激的褐鳟鱼的血浆促肾上腺皮质激素（ACTH）和皮质醇水平有显著影响。E处理显著提高了虹鳟鱼ACTH和皮质醇的静息水平，KT显著抑制了虹鳟鱼静息ACTH水平，尽管未观察到KT对基线皮质醇水平有影响。一小时的禁闭应激增加了虹鳟鱼的ACTH水平，但在植入T和KT的鱼中增加的幅度小于假植入鱼。在应激诱导的血浆皮质醇水平中观察到类似模式，其中虹鳟鱼的T和KT处理导致血浆皮质醇水平降低超过50%，而植入E则显著增加应激诱导的血浆皮质醇水平。在经受96小时禁闭应激的褐鳟中，在禁闭开始后1小时内，植入T和KT的鱼中应激诱导的血浆ACTH和血浆皮质醇的增加显著低于假植入对照。然而，在连续禁闭的96小时期间的后续采样点，这些差异没有持续存在。尽管如此，植入E的褐鳟在整个禁闭期间的总体平均ACTH水平显著升高，而植入KT的鱼则显著降低。植入T和KT的鱼的总体平均皮质醇水平显著较低。在未处理的成熟雌性鳟鱼中，在禁闭应激期间未观察到在E处理的未成熟鱼中观察到的应激反应性增强，其血浆E水平自然较高。然而，未处理的成熟雄性鳟鱼对禁闭的皮质醇反应显著降低。提示性腺类固醇参与鲑科鱼类垂体-肾间轴的基线和应激诱导活动的调节。
