Sugden David
Centre for Reproduction, Endocrinology and Diabetes, School of Biomedical Sciences, Kings College London, London Bridge, London SE1 1UL, UK.
J Neurochem. 2003 Sep;86(5):1308-11. doi: 10.1046/j.1471-4159.2003.01959.x.
A second gene encoding a functional tryptophan hydroxylase activity has recently been described (TPH2), which is expressed abundantly in brainstem, the primary site of serotonergic neurons in the CNS. As serotonin (5-HT) has an important role as a precursor of the nocturnal synthesis of the pineal gland hormone, melatonin, it was of interest to determine the relative expression of TPH1 and 2 mRNA in the rat pineal during the light:dark (L:D) cycle using sensitive real-time RT-PCR assays which were developed for each TPH isoform. TPH1 mRNA expression was 105-fold more abundant in rat pineal than TPH2, and showed a significant approximately 4-fold nocturnal increase in expression which may contribute to the previously described nocturnal increase in pineal tryptophan hydroxylase activity. TPH2 expression within the gland showed no significant variation with time of day and was very low (approximately 300 copies/gland) indicating expression in the small proportion of "non-pinealocyte" cells in the gland.
最近发现了另一个编码功能性色氨酸羟化酶活性的基因（TPH2），它在脑干中大量表达，而脑干是中枢神经系统中血清素能神经元的主要部位。由于血清素（5-HT）作为松果体激素褪黑素夜间合成的前体具有重要作用，因此利用为每种TPH亚型开发的灵敏实时逆转录聚合酶链反应（RT-PCR）检测法来确定大鼠松果体在光暗（L:D）周期中TPH1和TPH2 mRNA的相对表达情况，这很有意义。TPH1 mRNA在大鼠松果体中的表达量比TPH2高105倍，并且显示出夜间表达量显著增加约4倍，这可能导致了先前描述的松果体色氨酸羟化酶活性的夜间增加。腺体内TPH2的表达在一天中的不同时间没有显著变化，且非常低（约300拷贝/腺体），表明其在腺体内一小部分“非松果体细胞”中表达。
