Messager S, Garabette M L, Hastings M H, Hazlerigg D G
Department of Agriculture and Forestry, Aberdeen Centre For Energy Regulation and Obesity, University of Aberdeen, UK.
Neuroreport. 2001 Mar 5;12(3):579-82. doi: 10.1097/00001756-200103050-00029.
Melatonin secretion by the pineal gland transduces photoperiod into a neuroendocrine signal. In the pars tuberalis (PT), we have shown that photoperiod modifies the amplitude of the clock gene Per1. The aim of this study was to test whether the endogenous melatonin signal is required for rhythmic expression of Per1 in the PT. Male Syrian hamsters housed in long days (LD, 16:8h light:dark) were pinealectomized and Per1 mRNA expression studied by in situ hybridization. Pinealectomy abolished the rhythm of Per1 expression in the PT, but had no effect on Per1 expression in the suprachiasmatic nucleus (SCN), or the ventromedial nucleus (VMH) of the hypothalamus. Interestingly, a single night-time injection of melatonin (25 microg), given to pinealectomized animals, failed to restore Per1 expression in the PT. These data demonstrate that Per1 expression in the PT is driven by melatonin, and that the features of the endogenous signal through which the Per1 expression is achieved cannot be reproduced by a single melatonin injection.
松果体分泌的褪黑素将光周期转化为一种神经内分泌信号。在结节部（PT），我们已经表明光周期会改变生物钟基因Per1的振幅。本研究的目的是测试PT中Per1的节律性表达是否需要内源性褪黑素信号。将饲养在长日照（LD，16:8小时光照：黑暗）条件下的雄性叙利亚仓鼠进行松果体切除，并通过原位杂交研究Per1 mRNA的表达。松果体切除消除了PT中Per1表达的节律，但对下丘脑视交叉上核（SCN）或腹内侧核（VMH）中Per1的表达没有影响。有趣的是，给松果体切除的动物在夜间单次注射褪黑素（25微克），未能恢复PT中Per1的表达。这些数据表明，PT中Per1的表达由褪黑素驱动，并且通过单次注射褪黑素无法重现实现Per1表达的内源性信号的特征。
