Kontir D M, Glance C A, Colby H D, Miles P R
Biochem Pharmacol. 1986 Aug 1;35(15):2569-75. doi: 10.1016/0006-2952(86)90055-9.
In order to study the metabolism of benzo[a]pyrene (BP), it must be dissolved in an organic solvent vehicle for delivery to the tissue. We studied the effects of five organic solvent vehicles, i.e. dimethyl sulfoxide (DMSO), acetone, methanol, ethanol, and ethyl acetate, on benzo[a]pyrene hydroxylase activity and the BP metabolite profile in rabbit lung microsomes. Fluorescence detection of 3- and 9-OH-BP was used to evaluate benzo[a]pyrene hydroxylase activity, and the BP metabolite profile was obtained by HPLC analysis. All solvent vehicles inhibited benzo[a]pyrene hydroxylase in a dose-dependent manner. When the smallest volume of each solvent (10 microliter/ml reaction mixture) was employed, the resulting enzyme activities as related to solvent type, from highest to lowest, were DMSO greater than or equal to methanol greater than ethanol greater than or equal to acetone greater than ethyl acetate. HPLC analysis of BP metabolites formed in the presence of the five solvent vehicles showed that production of all metabolites was greatest when DMSO was used and that linearity of product formation was retained longer with DMSO. The metabolites produced when DMSO was used as the solvent were BP-9,10-diol, BP-4,5-diol, BP-7,8-diol, BP-1,6-quinone, BP-3,6-quinone and 3-OH-BP. A similar metabolite profile was obtained when reactions were carried out with methanol as the solvent vehicle, although the magnitude of production was less than with DMSO. When acetone was used, there were greater amounts of BP-4,5-diol and BP quinone formation and lesser amounts of 3-OH-BP formed than with DMSO or methanol. When ethanol or ethyl acetate was used as a solvent, BP-9,10-diol and 3-OH-BP were the only metabolites produced. These results indicate that all solvent vehicles studied inhibit benzo[a]pyrene hydroxylase from rabbit lung microsomes in a dose-dependent manner and that the magnitudes and types of metabolites formed are highly dependent upon the specific solvent used as the vehicle. The study also indicates that DMSO is probably the solvent vehicle of choice for study of BP metabolism in rabbit lung microsomes.
为了研究苯并[a]芘（BP）的代谢情况，必须将其溶解于有机溶剂载体中以便输送至组织。我们研究了五种有机溶剂载体，即二甲基亚砜（DMSO）、丙酮、甲醇、乙醇和乙酸乙酯，对兔肺微粒体中苯并[a]芘羟化酶活性及BP代谢物谱的影响。采用对3-和9-羟基-BP的荧光检测来评估苯并[a]芘羟化酶活性，并通过高效液相色谱（HPLC）分析获得BP代谢物谱。所有溶剂载体均以剂量依赖性方式抑制苯并[a]芘羟化酶。当使用每种溶剂的最小体积（10微升/毫升反应混合物）时，与溶剂类型相关的所得酶活性从高到低依次为：DMSO≥甲醇＞乙醇≥丙酮＞乙酸乙酯。对在五种溶剂载体存在下形成的BP代谢物进行的HPLC分析表明，当使用DMSO时所有代谢物的生成量最大，并且使用DMSO时产物形成的线性保持时间更长。以DMSO作为溶剂时产生的代谢物为BP-9,10-二醇、BP-4,5-二醇、BP-7,8-二醇、BP-1,6-醌、BP-3,6-醌和3-羟基-BP。当以甲醇作为溶剂载体进行反应时，获得了类似的代谢物谱，尽管生成量的幅度小于使用DMSO时。当使用丙酮时，与使用DMSO或甲醇相比，BP-4,5-二醇和BP醌的生成量更多，而3-羟基-BP的生成量更少。当使用乙醇或乙酸乙酯作为溶剂时，BP-9,10-二醇和3-羟基-BP是仅有的产生的代谢物。这些结果表明，所研究的所有溶剂载体均以剂量依赖性方式抑制兔肺微粒体中的苯并[a]芘羟化酶，并且形成的代谢物的量和类型高度依赖于用作载体的特定溶剂。该研究还表明，DMSO可能是用于研究兔肺微粒体中BP代谢的首选溶剂载体。
