ISOLATION OF RAT INTESTINAL MICROSOMES WITH STABLE CYTOCHROME-P-450 AND THEIR METABOLISM OF BENZO (ALPHA)PYRENE
ISOLATION OF RAT INTESTINAL MICROSOMES WITH STABLE CYTOCHROME-P-450 AND THEIR METABOLISM OF BENZO (ALPHA)PYRENE
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DOI：
10.1016/0003-9861(76)90420-3
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发表时间：
1976-01-01
影响因子：
3.9
通讯作者：
ORRENIUS, SG
中科院分区：
文献类型：
--
作者：
STOHS, SJ;GRAFSTROM, RC;ORRENIUS, SG
建立了一种从大鼠肠粘膜中分离具有稳定细胞色素P-450的微粒体的方法。通过在匀浆介质中加入胰蛋白酶抑制剂、甘油和肝素来保存血红素蛋白。本文研究了对照组和苯巴比妥（Pb）和3-甲基胆蒽（MC）处理组大鼠血红素蛋白的光谱特性。在喂养的动物中，口服给予MC导致苯并（α）芘（BP）单加氧酶在24小时内与细胞色素P-450（P-448）的同时增加，但对NADPH-细胞色素c还原酶活性没有影响。MC对BP单加氧酶和细胞色素P-450（P-448）的影响早在口服给药后1.5 h就已观察到。铅处理增加细胞色素P-450水平，但对NADPH-细胞色素c还原酶活性没有影响，BP单加氧酶的影响相对较小。在禁食动物中，MC也产生了BP单加氧酶活性的大幅增加相比，对照组动物。在7 μ M α-萘黄酮、BP单加氧酶在MC处理大鼠的微粒体中被抑制96%，在对照动物的微粒体中被刺激4.5倍。BP代谢产物的模式是类似的肠微粒体从控制和MC处理的大鼠，但不同的肝微粒体产生的急剧。BP的4，5-氧化物是主要肠代谢物之一，孵育5 min后仅形成少量二氢二醇。肠粘膜中存在的细胞色素P-450连接的单加氧酶系统在诱导特性、底物特异性和BP代谢物模式方面与肝脏系统显着不同。
A procedure was developed for the isolation of microsomes from rat intestinal mucosa with stable cytochrome P-450. Preservation of the hemoprotein was obtained by including trypsin inhibitor, glycerol and heparin in the homogenization medium. The spectral properties of the hemoprotein from control and phenobarbital (Pb)- and 3-methylcholanthrene (MC)-treated rats were examined. In fed animals, MC given orally resulted in a 30-fold stimulation of benzo(.alpha.)pyrene (BP) monooxygenase within 24 h with a simultaneous increase in cytochrome P-450 (P-448) but had no effect on NADPH-cytochrome c reductase activity. The effect of MC on BP monooxygenase and cytochrome P-450 (P-448) was seen as early as 1.5 h after oral administration. Pb treatment increased cytochrome P-450 levels but had no effect on NADPH-cytochrome c reductase activity and comparatively little effect on BP monooxygenase. In fasted animals, MC also produced large increases in BP monooxygenase activity when compared to control animals. At 7 .mu.M .alpha.-naphthoflavone, BP monooxygenase was inhibited 96% in microsomes from MC-treated rats and stimulated 4.5-fold in microsomes from control animals. The pattern of BP metabolites was similar for intestinal microsomes from control and MC-treated rats but differed sharply from that produced by hepatic microsomes. The 4,5-oxide of BP was 1 of the major intestinal metabolites with only small amounts of dihydrodiols being formed after a 5 min incubation. The cytochrome P-450-linked monooxygenase system present in the intestinal mucosa differs markedly from the hepatic system with regard to induction properties, substrate specificity and pattern of BP metabolites.