Craft C M, Morgan W W, Reiter R J
Neuroendocrinology. 1984 Mar;38(3):193-8. doi: 10.1159/000123890.
The purpose of this study was to examine the 24-hour variation in endogenous tyrosine hydroxylase (TH) activity and thus catecholamine (CA) synthesis in the hamster and rat pineal gland. To determine CA synthesis a time course of the accumulation of dihydroxyphenylalanine (DOPA) after DOPA decarboxylase inhibition with m-hydroxybenzylhydrazine (NSD-1015) was measured at 0, 15 and 30 min by liquid chromatography with electrochemical detection. Animals were under long photoperiods (LD 14:10; lights on at 06.00 h). In the hamster pineal gland, CA synthesis was greater in the dark (24.00 h) (0.017 ng/pineal/min) than in the light (12.00 h) (0.008 ng/pineal/min). Similarly, CA synthesis in the rat pineal was 0.037 ng/pineal/min (dark) and 0.005 ng/pineal/min (light). In a 24-hour study, animals were injected with NSD-1015,30 min prior to killing to determine if 24-hour changes were present in CA synthesis. In the hamster, DOPA in the dark (p less than 0.001) was significantly greater than in the light (1.33 +/- 0.42 ng/pineal at 06.00 h; 0.33 +/- 0.07 at 13.00 h) in this study. No significant difference was measured in norepinephrine (NE) concentration during this 24-hour period. In the rat, DOPA accumulation was significantly different (p less than 0.001) in the dark as compared to the light (0.86 +/- 0.09 ng/pineal at 03.00 h; 0.21 +/- 0.08 at 12.30 h). Within this 24-hour period, NE concentration fluctuated significantly between 2.28 +/- 0.33 ng/pineal (15.30 h) to 4.65 +/- 0.59 (05.30 h). These results indicate for the first time a definite 24-hour rhythm in endogenous TH activity and NE synthesis in the hamster pineal gland even though NE content does not change. In addition, a 24-hour change in CA synthesis and content is present in the rat pineal gland.
本研究的目的是检测仓鼠和大鼠松果体中内源性酪氨酸羟化酶（TH）活性的24小时变化，以及由此引起的儿茶酚胺（CA）合成的变化。为了测定CA的合成，在用间羟基苄基肼（NSD - 1015）抑制多巴脱羧酶后，于0、15和30分钟通过液相色谱 - 电化学检测法测定二羟基苯丙氨酸（DOPA）的积累时间进程。动物处于长光照周期（LD 14:10；6:00开灯）。在仓鼠松果体中，黑暗（24:00 h）时CA的合成量（0.017 ng/松果体/分钟）高于光照（12:00 h）时（0.008 ng/松果体/分钟）。同样，大鼠松果体中CA的合成量在黑暗时为0.037 ng/松果体/分钟，在光照时为0.005 ng/松果体/分钟。在一项24小时的研究中，在处死动物前30分钟给它们注射NSD - 1015，以确定CA合成中是否存在24小时变化。在本研究中，仓鼠黑暗时的DOPA量（p小于0.001）显著高于光照时（6:00 h时为1.33±0.42 ng/松果体；13:00 h时为0.33±0.07）。在这24小时期间，去甲肾上腺素（NE）浓度没有显著差异。在大鼠中，黑暗时的DOPA积累量与光照时相比有显著差异（p小于0.001）（3:00 h时为0.86±0.09 ng/松果体；12:30 h时为0.21±0.08）。在这24小时内，NE浓度在2.28±0.33 ng/松果体（15:30 h）至4.65±0.59（05:30 h）之间有显著波动。这些结果首次表明，即使NE含量不变，仓鼠松果体中内源性TH活性和NE合成也存在明确的24小时节律。此外，大鼠松果体中CA的合成和含量也存在24小时变化。
