EXPRESSION OF FUNCTIONAL CYTOCHROME P4501A1 IN HUMAN EMBRYONIC HEPATIC TISSUES DURING ORGANOGENESIS
EXPRESSION OF FUNCTIONAL CYTOCHROME P4501A1 IN HUMAN EMBRYONIC HEPATIC TISSUES DURING ORGANOGENESIS
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DOI：
10.1016/0006-2952(94)00493-6
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发表时间：
1995-03-01
影响因子：
5.8
通讯作者：
JUCHAU, MR
中科院分区：
文献类型：
--
作者：
YANG, HYL;NAMKUNG, MJ;JUCHAU, MR
用化学抑制剂和细胞色素p4501 A催化的乙氧基试卤灵（乙氧基吩恶嗪酮）O-脱乙基化和2-乙酰氨基芴（N-2-芴基乙酰胺）环羟基化特异性抑制抗体进行的研究表明，1A亚家族的细胞色素P450在妊娠早期（50-60天）的人胚胎肝组织中功能性表达。肝微粒体酶催化2-乙酰氨基芴的N-羟基化或甲氧基试卤灵的O-去甲基化的可检测能力的缺乏表明功能性细胞色素P4501 A2在人胚胎肝组织中表达最低或可忽略。相比之下，深刻的抑制环羟基化的2-乙酰氨基芴和O-脱乙基化的乙氧基试卤灵的7，8-benzopyranone以及抗细胞色素P4501 A1抗体表明存在显着水平的功能性细胞色素P4501 A1在肝微粒体的人胚胎。利用特异性寡核苷酸引物的逆转录聚合酶链反应，我们还检测到细胞色素P4501 A1 mRNA在人胚肝中的显着表达。聚合酶链反应扩增、克隆和测序结果表明，人胚胎组织中细胞色素P4501 A1 mRNA的表达与成人组织中细胞色素P4501 A1 mRNA的表达是一致的。研究结果对已知是细胞色素P4501 A1的底物、抑制剂或诱导剂的化学品的胚胎毒性效应以及孕妇接触的化学品具有重要意义。
Investigations with chemical inhibitors and with inhibitory antibodies specific for cytochrome p4501A-catalyzed ethoxyresorufin (ethoxyphenoxazone) O-deethylation and 2-acetylaminofluorene (N-2-fluorenylacetamide) ring hydroxylation indicated that cytochrome(s) P450 of the 1A subfamily was functionally expressed in human embryonic hepatic tissues at very early stages (days 50-60) of gestation. Lack of detectable capacity of hepatic microsomal enzymes to catalyze either N-hydroxylation of 2-acetylaminofluorene or O-demethylation of methoxyresorufin indicated that functional cytochrome P4501A2 is expressed minimally or negligibly in human embryonic hepatic tissues. By contrast, profound inhibition of the ring hydroxylation of 2-acetylaminofluorene and of the O-deethylation of ethoxyresorufin by 7,8-benzoflavone as well as by anti-cytochrome P4501A1 antibodies indicated the presence of significant levels of functional cytochrome P4501A1 in hepatic microsomes of human embryos. Using the reverse transcriptase-linked polymerase chain reaction with specific oligonucleotide primers, we also detected significant expression of cytochrome P4501A1 mRNA in human embryonic livers. Polymerase chain reaction amplification, cloning and sequencing of the corresponding cDNA provided evidence that the cytochrome P4501A1 mRNA expressed in human embryonic tissues was identical to that expressed in adult human tissues. The results of the study have important implications in terms of the embryotoxic effects of chemicals that are known to be substrates, inhibitors or inducers of cytochrome P4501A1 and to which pregnant women are exposed.