Age-related changes in serum melatonin in mice: higher levels of combined melatonin and 6-hydroxymelatonin sulfate in the cerebral cortex than serum, heart, liver and kidney tissues
Age-related changes in serum melatonin in mice: higher levels of combined melatonin and 6-hydroxymelatonin sulfate in the cerebral cortex than serum, heart, liver and kidney tissues
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DOI：
10.1111/j.1600-079x.2004.00120.x
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发表时间：
2004-05-01
影响因子：
10.3
通讯作者：
Bondy, SC
中科院分区：
文献类型：
--
作者：
Lahiri, DK;Ge, YW;Bondy, SC
测定了小鼠不同组织中褪黑激素和6-羟基褪黑激素硫酸盐水平的变化以及膳食褪黑激素对其水平的影响。褪黑激素的水平最高的血清，其次是肝脏，肾脏，大脑皮层和心脏作为测量的定量和敏感的酶标记免疫吸附测定（ELISA）。血清褪黑激素水平随着年龄的增长而下降，27个月大的小鼠相对于12个月大的小鼠减少了80%。在各种组织中独立测量6-羟基褪黑素硫酸盐的水平。褪黑激素代谢产物6-羟基褪黑激素硫酸盐的水平在所有测试的组织中显著高于游离褪黑激素。6-羟基褪黑激素硫酸盐的水平最高的大脑皮层，其次是血清，心脏，肾脏和肝脏。在12个月大的小鼠中，6-羟基褪黑激素硫酸盐浓度比大脑皮层中的褪黑激素浓度高约1000倍，仅比血清中的褪黑激素浓度高3倍。因此，脑中只有0.1%的总褪黑激素以游离和非结合形式存在，但血清中的相应值为27.4%。大脑皮层中的褪黑素和6-羟基褪黑素硫酸盐的含量比对照组小鼠的其他组织高。青年和老年小鼠之间的6-羟基褪黑素硫酸盐水平没有显着变化。血清样本中的血清素或皮质醇水平也没有年龄依赖性变化。膳食补充褪黑激素导致血清和所有其他组织样本中褪黑激素水平显着增加。因此，任何与年龄相关的组织褪黑激素的下降可以通过补充膳食褪黑激素来逆转。
Age-related changes in levels of melatonin and 6-hydroxymelatonin sulfate and effects of dietary melatonin on their levels in different tissues were determined in mice. Levels of melatonin were highest in the serum followed by liver, kidney, cerebral cortex and heart as measured by a quantitative and sensitive enzyme-labeled immunosorbent assay (ELISA). Serum melatonin levels decreased with age, and were reduced by 80% in 27-month old mice relative to 12-month old mice. Levels of 6-hydroxymelatonin sulfate were measured independently in various tissues. Levels of the melatonin metabolite, 6-hydroxymelatonin sulfate were significantly higher than free melatonin in all tissues tested. Levels of 6-hydroxymelatonin sulfate were highest in the cerebral cortex followed by the serum, heart, kidney, and liver. In 12-month old mice 6-hydroxymelatonin sulfate concentration was approximately 1000-fold greater than that of melatonin in the cerebral cortex, it was only 3-fold greater than melatonin levels in the serum. Thus only 0.1% of total melatonin in the brain was present in the free and unconjugated form but the corresponding value for serum was 27.4%. The cerebral cortex had the highest levels of combined melatonin and 6-hydroxymelatonin sulfate than other tissue tested in control mice. There was no significant change in 6-hydroxymelatonin sulfate levels between young and old mice. There was also no age-dependent change in levels of serotonin or cortisol in the serum samples. Dietary supplementation with melatonin resulted in a significant increase in levels of melatonin in the serum and all other tissue samples tested. Thus, any age-related decline of tissue melatonin can be reversed by supplementation with dietary melatonin.