A 15-minute light pulse during darkness prevents the antigonadotrophic action of afternoon melatonin injections in male hamsters.
A 15-minute light pulse during darkness prevents the antigonadotrophic action of afternoon melatonin injections in male hamsters.
复制标题
黑暗中 15 分钟的光脉冲可以阻止雄性仓鼠下午注射褪黑激素的抗促性腺激素作用。
DOI：
10.1007/bf02219498
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发表时间：
1982
影响因子：
3.2
通讯作者：
Kosub,KY
中科院分区：
文献类型：
--
作者：
Reiter,RJ;Hurlbut,EC;King,TS;Richardson,BA;Vaughan,MK;Kosub,KY
当成年雄性叙利亚仓鼠每天在14h光照和10h黑暗中(灯从0600-2000h亮起)，松果体褪黑素水平在0500h达到峰值(705pg/腺)，当从2300-2315h(熄灯后3h)用15min的光脉冲中断暗：暗周期时，松果体褪黑素的最高水平约为400pg/腺。最后，如果在0200-0215小时(熄灯后6小时)给予15分钟的光脉冲，松果体褪黑激素的夜间升高完全消失。在进行了这些观察之后，设计了第二个实验，以确定下午注射褪黑激素抑制仓鼠繁殖的能力，这些仓鼠保持在不间断的14：10周期下，或者在相同的光照制度下，用15分钟的光脉冲(0200-0215h)中断黑暗阶段。在不间断的光：暗程序中，每天下午注射25μg褪黑素，可导致睾丸和附性器官在11周内萎缩。相反，如果黑暗阶段在0200-0215h之间被光照中断，下午注射褪黑素不能抑制生殖器官的生长。这些发现表明，外源性服用褪黑素通常与内源性产生的褪黑素协同作用，导致仓鼠性腺退化。
When adult male Syrian hamsters were maintained under 14 h light and 10 h darkness daily (lights on from 0600-2000 h), peak pineal melatonin levels (705 pg/gland) were attained at 0500 h. When the dark phase of the light:dark cycle was interrupted with a 15 min pulse of light from 2300–2315 h (3 h after lights out), the highest melatonin levels achieved was roughly 400 pg/gland. Finally, if the 15 min pulse of light was given at 0200–0215 h (6 h after lights out) the nocturnal rise in pineal melatonin was completely abolished. Having made these observations, a second experiment was designed to determine the ability of afternoon melatonin injections to inhibit reproduction in hamsters kept under an uninterrupted 14∶10 cycle or under the same lighting regimen where the dark phase was interrupted with a 15 min pulse of light (0200–0215 h). In the uninterrupted light:dark schedule the daily afternoon injection of 25 μg melatonin caused the testes and the accessory sex organs to atrophy within 11 weeks. Conversely, if the dark phase was interrupted with light between 0200–0215 h, afternoon melatonin injections were incapable of inhibiting the growth of the reproductive organs. The findings suggest that exogenously administered melatonin normally synergizes with endogenously produced melatonin to cause gonadal involution in hamsters.