PHOSPHOLIPID TRANSFER DURING INTESTINAL ABSORPTION

胆汁中磷脂：胆盐混合胶束的形成 以及它们分泌到肠腔和从肠腔吸收 是必不可少的排泄胆固醇，消化和 脂肪的吸收和乳糜微粒的形成。 很长的- 这项研究长期目标是了解这些高度 水不溶性磷脂在 不同的疏水环境， 肝细胞到肠上皮细胞。 该提案重点 在整个过程中的三个步骤：1）之间的转移 胶束; 2）从胶束转移到肠细胞刷状缘 膜;和3）转移穿过刷状缘膜。 荧光（NBD）标记的磷脂和溶血磷脂将 用于监测每一个项目所涉及的快速转移， 以上案件。 NBD荧光团的光谱性质 （量子产率对环境极性的敏感性， 在高浓度下自猝灭，以及被Co++猝灭） 将用于检测NBD标记磷脂的转移 从一个地方到另一个地方 使用这些技术， 配备有停流快速混合装置的荧光计可以 检测胶束之间发生的快速磷脂转移 和细胞膜，以及跨细胞膜。 动力学建模将是 用于确定每一个涉及的机制或机制 上述过程。

The formation of mixed phospholipid: bile salt micelles in the bile and their secretion into and absorption from the intestinal lumen are essential to the excretion of cholesterol, the digestion and absorption of fats, and the formation of chylomicrons. The long- term objective of this research is to understand how these highly water-insoluble phospholipids are rapidly transferred between the different hydrophobic environments during their movement from liver hepatocytes to intestinal enterocytes. This proposal focuses on three steps in the overall process: 1) transfer between micelles; 2) transfer from micelles to the enterocyte brush-border membrane; and 3) transfer across the brush-border membrane. Fluorescent (NBD)-labeled phospholipids and lysophospholipids will be used to monitor the rapid transfer involved in each of the above cases. The spectral properties of the NBD fluorophore (sensitivity of quantum yield to the polarity of the environment, self-quenching at high concentrations, and quenching by Co++) will be used to detect the transfer of NBD-labeled phospholipids from one location to another. Using these techniques, a fluorometer equipped with a stopped-flow rapid mixing device can detect the fast phospholipid transfer that occurs between micelles and membranes, and across membranes. Kinetic modeling will be used to determine the mechanism or mechanisms involved in each of the above processes.