INTESTINAL P4501A--DIETARY REGULATION OF DETOXIFICATION

肠道P4501A--排毒饮食调节

• 批准号: 2155106
• 负责人: LAURENCE S KAMINSKY
• 金额: $ 12.41万
• 依托单位: WADSWORTH CENTER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-01 至 1997-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2155106
• 关键词: chemical carcinogen; cytochrome P450; detoxification; dietary constituent; dietary control; dietary iron; dietary trace element; environmental toxicology; excretion; gene induction /repression; glucocorticoids; immunocytochemistry; laboratory rat; northern blottings; nutrition related tag; polymerase chain reaction; radiotracer; selenium; small intestines; vegetables; western blottings

The long-term objective of this application is to develop methods for protection against orally ingested pollutants and toxicants by dietary manipulation of small intestinal cytochromes P4501A. The hypothesis is that induction of small intestinal cytochrome P4501A levels by dietary constituents serves as a major role in protecting the organism from bioactivatable chemical carcinogens and other toxicants. The P4501A(s) protect by facilitating xenobiotic metabolism and excretion to the intestinal lumen, and/or by bioactivating the xenobiotics, which then bind to enterocyte constituents and are cleared with the sloughed-off enterocyte. The following specific aims will test this hypothesis: 1. To determine the basal P450 constituents of intestine of rats fed a diet based on purified components. These studies will provide a basal metabolic background from which to assess effects of induction by dietary constituents on intestinal P4501A metabolism of xenobiotics. 2. To characterize the induction of rat intestinal P4501A forms by beta- naphthoflavone (BNF) as a model for dietary inducers. Studies will include effects of route of BNF administration, BNF does, synergistic enhancement of induction by glucocorticoids, time to achieve induction, duration of induction, situation of induced P4501A along the length of small intestine, situation of induced P4501A in the crypt or villus, relative extents of induction of P4501A and 1A2 and the basis for differences from hepatic induction of these forms. 3. To determine the role of dietary constituents in regulating intestinal P4501A forms. Initially dietary iron, selenium, cruciferous regulating intestinal P4501A forms. Initially dietary iron, selenium, cruciferous vegetables and indole-e-carbinol will be investigated and other examples will be sought. Possible novel mechanisms of induction of intestinal P4501A by dietary constituents will be investigated. Techniques to be applied to the above aims include reverse transcriptase-PCR, immunoblots, Northern blots, immunohistochemistry, and metabolic activity measurements. 4. To determine the capability of small intestinal P4501A to produce presystematic xenobiotic excretion and thus detoxification: a) An ex vivo intestinal preparation will be used to determine the relative extents of enterocyte elimination of xenobiotic or metabolite into the intestinal lumen or systemic circulation. The former case would result in detoxification, the latter case would have potential toxic consequences. b) Radiolabeled xenobiotics will be used to assess the capacity of intestinal P4501A in vivo to detoxify by enhancing excretion as conjugated or free metabolite or metabolite bound to sloughed-off enterocyte. These studies will provide the basis for manipulating the protective role of intestinal P4501A by dietary factors, thus by achieving additional protection against the systemic toxicity of ingested xenobiotics.

本申请的长期目标是开发用于以下的方法： 通过饮食预防口服摄入的污染物和有毒物质 小肠细胞色素P4501 A的操作。 这个假设是 饮食诱导小肠细胞色素P4501 A水平 成分在保护生物体免受 可生物活化的化学致癌物和其他有毒物质。 P4501A（S） 通过促进异生物质代谢和排泄到体内来保护 肠腔，和/或通过生物活化外源性物质，然后 与肠上皮细胞成分结合， 肠上皮细胞 以下具体目标将测试这一假设：1。 测定正常大鼠肠道P450的基础成分 基于纯化的成分。 这些研究将提供一个基础 代谢背景，以评估饮食诱导的影响 P4501 A代谢的影响。 2. 到 表征β-氨基丁酸对大鼠肠P4501 A形式的诱导， 萘酮（BNF）作为膳食诱导剂的模型。 研究将 包括BNF给药途径、BNF剂量、协同作用 糖皮质激素诱导的增强，达到诱导的时间， 诱导持续时间，诱导的P4501 A沿着长度的情况 小肠，在隐窝或绒毛中诱导的P4501 A的情况， P4501 A和1A 2诱导的相对程度以及 与这些形式的肝诱导的差异。 3. 确定 膳食成分在调节肠道P4501 A形式中的作用。 最初膳食铁、硒、十字花科调节肠道 P4501 A表格。 最初膳食铁、硒、十字花科蔬菜 和吲哚-e-甲醇将进行研究，其他例子将 寻找。 诱导肠道P4501 A的可能新机制 将调查饮食成分。 技术应用于 上述目的包括逆转录酶-PCR、免疫印迹、北方 印迹、免疫组织化学和代谢活性测量。 4. 确定小肠P4501 A产生 系统前异生物质排泄，从而解毒：a）一个前 体内肠道准备将用于确定相对 肠上皮细胞将外源性物质或代谢物排除到 肠腔或体循环。 前一种情况会导致 在解毒方面，后一种情况会有潜在的毒性， 后果 B）放射性标记的外源性物质将用于评估 肠P4501 A在体内通过增强排泄解毒的能力 结合或游离代谢物或与脱落物结合的代谢物 肠上皮细胞 这些研究将为操纵 肠道P4501 A的保护作用，饮食因素，因此， 获得额外的保护，防止摄入的 异生物质