Miller M S, Jones A B, Chauhan D P, Park S S, Anderson L M
Perinatal Carcinogenesis Section, National Cancer Institute, Frederick, Maryland 21702.
Biochem Biophys Res Commun. 1991 Apr 15;176(1):280-7. doi: 10.1016/0006-291x(91)90921-s.
Pregnant Sprague-Dawley rats were treated with a single ip dose of either olive oil or 40 mg/kg of 3-methylcholanthrene on gestation day 20 and sacrificed at various times after injection. Determination of aryl hydrocarbon hydroxylase activity 24 hr after injection revealed that treatment with 3-methylcholanthrene resulted in a 10.5-fold stimulation of enzymatic activity in liver 800 x g supernatants. Western blot analysis with monoclonal antibody 1-7-1 confirmed these results and demonstrated the presence of a 3-methylcholanthrene-inducible P-450 isozyme. Using Northern and slot blot techniques, the induction of steady-state levels of CYPIA1 RNA was shown to occur as early as 4 hr following 3-methylcholanthrene injection. CYPIA1 RNA levels were induced 31.6-fold over values obtained from oil-treated tissues at this time. This appears to be the optimal time to study changes in the levels of CYPIA1 RNA gene expression in the fetus following transplacental exposure to polycyclic aromatic hydrocarbons. By 12 to 24 hr postinjection, the induction of CYPIA1 RNA levels declined to 3.5- to 8.5-fold above control values. These results demonstrate that the kinetics of induction of the CYPIA1 gene during the fetal period differed from that seen in adults.
在妊娠第20天，给怀孕的Sprague-Dawley大鼠腹腔注射单剂量的橄榄油或40 mg/kg的3-甲基胆蒽，并在注射后的不同时间处死。注射后24小时测定芳烃羟化酶活性，结果显示，用3-甲基胆蒽处理导致肝脏800 x g上清液中的酶活性受到10.5倍的刺激。用单克隆抗体1-7-1进行的蛋白质印迹分析证实了这些结果，并证明存在一种3-甲基胆蒽诱导的P-450同工酶。使用Northern印迹和狭缝印迹技术，结果显示，早在3-甲基胆蒽注射后4小时就出现了CYPIA1 RNA稳态水平的诱导。此时，CYPIA1 RNA水平比从油处理组织获得的值诱导了31.6倍。这似乎是研究经胎盘暴露于多环芳烃后胎儿中CYPIA1 RNA基因表达水平变化的最佳时间。注射后12至24小时，CYPIA1 RNA水平的诱导下降至比对照值高3.5至8.5倍。这些结果表明，胎儿期CYPIA1基因的诱导动力学与成年期不同。
