Lerchl A
Institute of Reproductive Medicine of the University, Münster, FRG.
Neurosci Lett. 1994 Jul 18;176(1):25-8. doi: 10.1016/0304-3940(94)90862-1.
Groups of young adult (1.7 months) and old adult (9.7 months) female Djungarian hamsters were exposed to short-day photo-periods (SD; 8L:16D) or long-day photoperiods (LD; 16L:8D) for 6 weeks. Pineal and serum melatonin rhythms were dampened in old SD animals when compared with young SD animals. The melatonin precursor serotonin showed diurnal variations with opposite phases to melatonin synthesis. However, pineal serotonin levels were even lower in old SD animals than in young SD animals, contrary to the expected accumulation of the precursor. The synthesis of a metabolite of serotonin, 5-hydroxyindoleacetic acid (5-HIAA), was significantly lower in younger hamsters, under both photoperiods. These results indicate that the age-associated decline in the production of melatonin is a consequence of an increased oxidation of its precursors.
将年轻成年（1.7个月）和老年成年（9.7个月）雌性黑线仓鼠分组，使其暴露于短日照光周期（SD；8小时光照：16小时黑暗）或长日照光周期（LD；16小时光照：8小时黑暗）下6周。与年轻的SD组动物相比，老年SD组动物的松果体和血清褪黑素节律受到抑制。褪黑素前体血清素呈现出与褪黑素合成相反相位的昼夜变化。然而，与预期的前体积累情况相反，老年SD组动物的松果体血清素水平甚至低于年轻SD组动物。在两种光周期条件下，年轻仓鼠体内血清素的代谢产物5-羟吲哚乙酸（5-HIAA）的合成均显著较低。这些结果表明，与年龄相关的褪黑素生成下降是其前体氧化增加的结果。
