FATTY ACID ASSIMILATION IN THE INTESTINE

这项研究的目的是研究无偿转让 肠道中的脂肪酸(FFA)在分子水平上的顺序 阐明游离脂肪酸同化的发生机制。这个 这些研究的最终目的是学习如何控制血脂。 通过调节速率限制过程进行的同化。这个 拟议的研究将解决我们在以下方面的知识差距 游离脂肪酸在肠腔内转运的调节 在肠细胞的细胞质内。所使用的方法将 是一个完整的模型，结合了纯化模型技术 具有重组的细胞膜系统的脂类系统和 细胞质成分。 最近的研究表明，在肠道脂质的过程中 消解时，形成两个产物相，一个是胶束相，一个是 单层囊泡期。拟议的研究将使用 申请人最近开发的荧光测定法用于比较 两种不同脂相中游离脂肪酸转移的动力学 受体膜，并确定其分子机制 以及从这些阶段中的每个阶段传输的速率限制步骤 发生。 肠细胞胞质内的大多数游离脂肪酸结合到 脂肪酸结合蛋白(S)。我们的初步研究已经 结果表明，当FFA与FABP结合时，脂肪酰链是 被高度限制在一个疏水口袋里。建议数 研究将继续调查这一现象的物理性质 FFA的FABP结合部位，并对FFA进行表征和比较 结合FABP与FFA结合膜，以评估 这些相互作用在细胞FFA同化中的相对作用。 另一个目标是系统地调查 FABP调节细胞内FFA的转运。这些研究将 从模型中检验比较和FFA的迁移动力学 膜和亚细胞膜到FABP，以及从FABP到 并将阐明FABP在细胞间相互作用中的确切作用。 肠上皮细胞膜FFA转移。 在分子水平上理解FFA同化将会 能够更有效地治疗几种病理生理学和 药物引起的吸收不良综合征，并将支持 继续开发口服给药系统。

The objective of this research is to study the transfer of free fatty acids (ffa) in the intestine at the molecular level, in order to elucidate the mechanisms by which ffa assimilation occurs. The ultimate aim of these studies is to learn how to control lipid assimilation by regulation of rate limiting processes. The proposed studies will address the gaps in our knowledge concerning the regulation of ffa transfer, both within the intestinal lumen and within the cytoplasm of the enterocyte. The approach used will be an integrated one, combining the techniques of purified model lipid systems with reconstituted systems of cell membranes and cytoplasmic components. Recent work has shown that during the course of intestinal lipid digestion, two product phase are formed, a micelle phase and a unilamellar vesicle phase. The proposed studies will use a fluorescence assay recently developed by the applicant to compare the kinetics of ffa transfer from these two distinct lipid phases to acceptor membranes, and to determine the molecular mechanisms and rate limiting steps by which transfer from each of these phases occurs. The majority of ffa within the enterocyte cytoplasm are bound to fatty acid binding protein(s) (FABP). Our preliminary studies have shown that when ffa are bound to FABP, the fatty acyl chain is highly constrained within a hydrophobic pocket. The proposed studies will continue to investigate the physical nature of the FABP binding site of ffa, and will characterize and compare ffa binding to FABP v. ffa binding to membranes, in order to assess the relative roles of these interactions in cellular ffa assimilation. A further goal is to systemically investigate the manner in which FABP modulates intracellular ffa transport. The studies will examine and compare and the transfer kinetics of ffa from model membranes and subcellular membranes to FABP, and from FABP to membranes, and will elucidate the precise role of FABP in inter- membrane ffa transfer in the enterocyte. An understanding of ffa assimilation at the molecular level will enable more effective treatment of several pathophysiological and drug-induced malabsorption syndromes, and will support the continued development of oral drug delivery systems.