Yamasaki H, Huberman E, Sachs L
J Biol Chem. 1975 Oct 10;250(19):7766-70.
Treatment of hamster BHK cells with N6,O2'-dibutyryl adenosine 3':5'-monophosphate (Bt2cAMP), aminophylline, theophylline, or papaverine increased the level of aryl hydrocarbon (benzo(a)pyrene) hydrolxylase activity. The highese increase, 100-fold, was obtained with Bt2cAMP plus aminophylline or theophylline. N2,O2-Dibutyryl guanosine 3':5'-monophosphate gave a lower induction than Bt2cAMP. The level of hydroxylase activity started to decrease 6 hours after treatment with the inducer and was reduced to almost the uninduced level after 24 hours. Repeated addition of Bt2cAMP and aminophylline did not prevent this decrease. The hydroxylase can also be induced by treating cells with benz(a)anthracene, and the level of this induced activity was maintained for 24 hours. Aminophylline gave a 2- to 8-fold stimulation of the induction by benz(a)anthracene. The enzyme activity induced by Bt2cAMP, aminophylline, and benz(a)anthracene converted benzo(a)pyrene to similar alkali-extractable metabolities with a fluorescence spectra similar to that of 3-hydroxybenzo(a)pyrene. These induced enzyme activities also showed a similar heat stability. Induction by Bt2cAMP and aminophylline, like induction by benz(a)anthracene, required continued protein synthesis and only an initial period of RNA synthesis. Compared to the benz(a)anthracene-induced hydroxylase with a Km of 4.3 muM, the hydroxylase induced by Bt2cAMP and aminophylline showed a Km of 0.14 muM, and was 100-fold more sensitive to inhibition by 7,8-benzoflavone. Increasing the serum concentration in the culture medium stimulated the induction by aminophylline but did not stimulate induction by benz(a)anthracene. The results indicate that aryl hydrocaarbon (benzo(a)pyrene) hydroxylase can be induced by compounds that increase the level of adenosine 3':5'-monophosphate and that this induction and induced enzyme activity differs from that caused by benz(a)anthracene.
用N6,O2'-二丁酰腺苷3':5'-单磷酸（Bt2cAMP）、氨茶碱、茶碱或罂粟碱处理仓鼠BHK细胞，可提高芳烃（苯并(a)芘）羟化酶的活性水平。Bt2cAMP与氨茶碱或茶碱联合使用时，活性增加幅度最大，可达100倍。N2,O2-二丁酰鸟苷3':5'-单磷酸的诱导作用低于Bt2cAMP。用诱导剂处理6小时后，羟化酶活性水平开始下降，24小时后降至几乎未诱导的水平。重复添加Bt2cAMP和氨茶碱并不能阻止这种下降。用苯并(a)蒽处理细胞也可诱导羟化酶，且这种诱导活性水平可维持24小时。氨茶碱可使苯并(a)蒽的诱导作用增强2至8倍。由Bt2cAMP、氨茶碱和苯并(a)蒽诱导产生的酶活性可将苯并(a)芘转化为类似的碱可提取代谢产物，其荧光光谱与3-羟基苯并(a)芘相似。这些诱导的酶活性也表现出相似的热稳定性。与苯并(a)蒽诱导的羟化酶（Km为4.3μM）相比，Bt2cAMP和氨茶碱诱导的羟化酶Km为0.14μM，对7,8-苯并黄酮抑制作用的敏感性高100倍。提高培养基中的血清浓度可刺激氨茶碱的诱导作用，但不能刺激苯并(a)蒽的诱导作用。结果表明，芳烃（苯并(a)芘）羟化酶可被能提高腺苷3':5'-单磷酸水平的化合物诱导产生，且这种诱导作用及诱导的酶活性与苯并(a)蒽引起的不同。
