Abstract: 　Cortisol content of successive separate by collected urine samples from the normal and suprachiasmatic nucleus (SCN ) lesioned tree shrews by radio immunoassay. The results showed that circadian rhythm of urine cortisol concent ration was of pronounced diurnal fluctuation. The peak value appeared at 10：00～12：00, bathymetron was at 0：00.The content of acrometron was about eight times deuse as that of bathymetron. The above rhythm was abolished after the SCN lesion. The results suggested that SCN was the important circadian pace maker of cortisol secretion in tree shrew.

Key words: Tree shrew (Tupaia belang erichinensis), Cortisol, Circadian rhythm, Suprachiasmatic nucleus

摘要： 用放射免疫方法对连续采集的正常树鼩及视交叉上核损毁树鼩尿中的皮质醇进行了测定, 以分析其尿中皮质醇浓度及排泄量的昼夜变动规律。结果表明, 正常树鼩尿中皮质醇的浓度及单位时间内的排泄量均具有明显的昼夜节律, 在一天中, 11：00前后的浓度最高, 0：00前后的浓度最低, 前者约为后者的8倍。视交叉上核损毁后, 树鼩皮质醇的这种昼夜节律消失,说明视交叉上核在树鼩中也是机体昼夜节律重要的振荡器。

关键词: 树, 皮质醇, 昼夜节律, 视交叉上核