Pineal Melatonin Content in Male Hamsters throughout the Seasonal Reproductive Cycle 1
Pineal Melatonin Content in Male Hamsters throughout the Seasonal Reproductive Cycle 1
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整个季节性生殖周期中雄性仓鼠的松果体褪黑素含量 1
DOI：
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
R. Reiter
中科院分区：
文献类型：
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作者：
M. Rollag;E. Panke;R. Reiter
摘要：雄性仓鼠以 10 周为间隔，连续暴露于长光周期（14 小时光照：10 小时黑暗）10 周，短光周期（8 小时光照：16 小时黑暗）30 周，然后再次暴露于长光周期 10 周，对松果体褪黑激素含量的日节律进行了表征。这些光周期操作引起了与该物种经历的季节性生殖周期相关的性腺变化。在最初的长光周期结束时，全天和黑暗的前 6 小时发现平均褪黑激素浓度为 79-114 皮克/腺体，在黑暗开始后 8 小时发现峰值浓度为 949 皮克/腺体。暴露于短光周期10、20或30周的仓鼠，全天和黑暗的前7小时松果体褪黑激素浓度范围为50至140皮克/腺体，在光到黑暗过渡后13小时峰值浓度为764至1025皮克/腺体。最后一组仓鼠在暴露于 30 周的短光周期后又经历了 10 周的长光周期，其褪黑激素浓度分布与第一组相似。事实上，如果松果体褪黑激素水平与吲哚分泌量有关，那么目前的结果并不支持需要显着改变松果体产生的褪黑激素数量来解释仓鼠季节性生殖变化的假设。特别是，该物种的光不反应性不能用松果体产生褪黑激素的能力耗尽来解释。
Abstract The daily rhythm in pineal melatonin content has been characterized at 10-week intervals in male hamsters sequentially exposed to long photoperiods (14 hr light: 10 hr dark) for 10 weeks, short photoperiods (8 hr light: 16 hr dark) for 30 weeks, and then long photoperiods once again for 10 weeks. These photoperiodic manipulations induced the gonadal changes associated with the seasonal reproductive cycle experienced by this species. At the end of the initial long photoperiod, mean melatonin concentrations of 79-114 pg/gland were found throughout the day and the first 6 hr of darkness and a peak concentration of 949 pg/gland was found 8 hr after the onset of dark. Hamsters exposed to short photoperiods for either 10, 20, or 30 weeks had pineal melatonin concentrations ranging from 50 to 140 pg/gland throughout the day and the first 7 hr of darkness and peak concentrations ranging from 764 to 1025 pg/gland 13 hr after the light to dark transition. The last group of hamsters, which had been in long photoperiods for 10 weeks after exposure to 30 weeks of short photoperiods, had a melatonin concentration profile similar to that of the first group. If, in fact, pineal melatonin levels are related to the amount of indole secreted then the present results do not support the hypotheses which require dramatic alterations in the quantity of melatonin produced by the pineal gland to explain seasonal reproductive changes in hamsters. In particular, photorefractoriness in this species cannot be explained by exhaustion of the capacity of the pineal gland to produce melatonin.