Effect of the exposure to circularly polarized magnetic field on the metabolism of pteridine and biogenic amines

四氢生物蝶呤(BH4)是芳香族氨基酸羟化的辅因子，其水平调节儿茶酚胺和吲哚胺生物合成途径中的起始酶和限速酶。其他一些蝶呤类药物，如新喋呤(NP)和蝶呤(AHP)，被认为与免疫和衰老有关。据报道，暴露在圆极化磁场中会降低褪黑素的水平。本研究的目的是确定小鼠暴露于圆极化磁场后各组织中蝶啶类药物水平的变化。每组5只雄性小鼠，开始时为5周，在1，3和6周期间连续暴露在0.5mT的圆极化磁场中。将假动物暴露于约0.14μT的杂散磁场中，在每个暴露周期结束时断头取小鼠组织，在-80℃下冷冻保存直至检测。从两组获得的数据均为co…与笼养对照组比较有显著差异。三组间差异有统计学意义，经t检验，三组间体重差异无统计学意义。暴露组各组织中NP和AHP水平均较其他组显著升高。接触组BH4含量显著降低，但三组间总生物蝶呤水平无明显差异。GTP环水解酶I和丙酮酰四氢蝶呤合成酶活性在三组间无明显差异，说明磁场对BH4的生物合成没有影响。由此推测，暴露在磁场中可能会影响二氢生物蝶呤还原为BH4。BH4水平的降低可能导致儿茶酚胺和吲哚胺含量的降低。进一步研究了圆极化磁场作用下神经递质水平的变化，以及线极化磁场对蝶啶水平的影响。较少

Tetrahydrobiopterin(BH4) is a putative cofactor for the hydroxylation of aromatic amino acids and its level has been indicated to regulate the initial and rate limiting enzymes in the pathway for biosynthesis of cateholamines and indolamines. Other pteridines, such as neopterin(NP) and pterin(AHP), are postulated to correlate with immunity and aging. It is reported that melatonin level is lowered by the exposure to circularly polarized magnetic field. The objective if this study is to determine the alteration of each pteridine level in mouse tissues under the exposure to circularly polarized magnetic field.Five male mice per group, five week-old at the start, were used and exposed continuously to 0.5 mT circularly polarized magnetic field in period of 1,3 and 6 weeks. The sham-animal was exposed to stray field about 0.14 μ T. Mouse tissues were obtained after decapitation at the end of each exposure period and stored frozen at -80 ℃ until assayed. Data obtained from both groups were co … More mpared with that cage control group. Statistical significance of different between three groups was performed by Students's t-testThere were no difference if body weights among three groups. The level of NP and AHP in tissues from exposed group were significantly increased from other groups. BH4 content was significantly decreased in the exposed group, although total biopterin level was not different among three groups. No differences of GTP cyclohydrolase I and pyruvoyltetrahydropterin synthase activities were recognized among three groups.These results suggests that BH4 biosynthesis is not affected by the exposure to magnetic field. The speculation leads to that the exposure to magnetic field may affect the reduction of quinonoid-dihydrobiopterin to BH4. The decreaqse of BH4 level may result in a lowering of amounts of ccatechoamines and indolamines. Further studies are carrying in the alteration of the neurotransmittance level under exposure to circularly polarized magnetic field and the effect of linearly polarized magnetic field on pteridine levels. Less