Perelló Mario, Chacon Fernando, Cardinali Daniel P, Esquifino Ana I, Spinedi Eduardo
Neuroendocrine Unit, Multidisciplinary Institute on Cell Biology (CONICET-CICPBA), La Plata, Argentina.
Life Sci. 2006 Mar 13;78(16):1857-62. doi: 10.1016/j.lfs.2005.08.029. Epub 2005 Nov 11.
This work analyzes the effect of social isolation of growing male rats on 24-h changes of plasma prolactin, growth hormone, ACTH and leptin, and on plasma and adrenal corticosterone concentrations. At 35 days of life, rats were either individually caged or kept in groups (6-8 animals per cage) under a 12:12 h light/dark schedule (lights on at 08:00 h). A significant arrest of body weight gain regardless of unchanged daily food intake was found in isolated rats after 2 weeks of isolation. On the 4th week, rats were killed at 6 time intervals during a 24-h cycle, beginning at 09:00 h. In isolated rats the 24-h pattern of all parameters tested became distorted, as assessed by Cosinor analysis. When analyzed as a main factor in a factorial analysis of variance, isolation decreased plasma prolactin and growth hormone, increased plasma leptin and corticosterone while decreased adrenal corticosterone. Plasma corticosterone levels correlated significantly with plasma ACTH and with adrenal corticosterone levels in group-caged rats only. These changes can be attributed to an effect of mild stress on the endogenous clock that modulates the circadian hormone release.
本研究分析了生长中的雄性大鼠社会隔离对血浆催乳素、生长激素、促肾上腺皮质激素（ACTH）和瘦素24小时变化的影响，以及对血浆和肾上腺皮质酮浓度的影响。在35日龄时，将大鼠分别单独饲养于笼中，或按12:12小时光照/黑暗周期（08:00开灯）进行群居饲养（每笼6 - 8只动物）。隔离2周后，发现隔离饲养的大鼠尽管每日食物摄入量未变，但体重显著停止增加。在第4周，从09:00开始，在24小时周期内的6个时间点处死大鼠。通过余弦分析评估，发现隔离饲养的大鼠所有检测参数的24小时模式均发生扭曲。在方差分析的析因分析中，将隔离作为主要因素分析时，隔离使血浆催乳素和生长激素降低，血浆瘦素和皮质酮增加，而肾上腺皮质酮降低。仅在群居饲养的大鼠中，血浆皮质酮水平与血浆ACTH以及肾上腺皮质酮水平显著相关。这些变化可归因于轻度应激对调节昼夜激素释放的内源性生物钟的影响。
