RAT INTESTINAL MEMBRANES: VITAMIN D-MEDIATED EFFECTS

大鼠肠膜：维生素 D 介导的作用

• 批准号: 3239368
• 负责人: THOMAS A BRASITUS
• 金额: $ 20.81万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3239368
• 关键词: brush border membrane; calcium transporting ATPase; cholecalciferol; gastrointestinal absorption /transport; hormone regulation /control mechanism; laboratory rat; lipid metabolism; liposomes; nutrition related tag; phosphatidylethanolamines; phospholipase D; small intestines; vitamin D deficiency

Prior studies by our laboratory have shown that vitamin D-deprivation for 11 to 18 weeks resulted in alterations in the lipid fluidity and fatty acid composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PR) of rat proximal small intestinal brush- border membranes. Moreover, administration of 1,25(OH)2D3 to D-deprived animals rapidly (1-2 h) corrected these membrane alterations, temporally preceding the earliest detectable stimulation of transmucosal Ca2+ transport by this hormone )(5 h). These observations led us to hypothesize that these vitamin D-induced membrane changes were responsible for this hormone's effects and Ca2+ transport. Based on these prior findings, the overall goal of the present proposal is to determine whether these vitamin D-induced brush-border membrane alterations are indeed responsible for its Ca2+ transport effects. To achieve this goal, tow sets of experiments are planned. First, weanling male-Wistar rats will be deprived of dietary and light sources of vitamin D for 14 weeks (group A). Age-matched dietary D-replete rats will serve as controls (group B). Rats from each group will be treated with analogs of vitamin D or vehicle, respectively. After 2-5 h, the rats will be sacrificed and brush-border membrane vesicles isolated. These preparations will be examined and compared with respect to their: 1) lipid fluidity; 2) lipid composition including individual molecular species of PC nd PE; 3) Ca2+ transport; and 4) various enzymatic activities. Once these studies are accomplished, membranes will be prepared from animals i groups A and B and treated in vitro with nonspecific lipid transfer protein together with synthetic liposomes in order to enrich these membranes with specific molecular species of PC and/or PE found to be altered in the earlier studies (see above). After treatment, membrane vesicles from both groups will be analyzed and compared with respect to their lipid composition, Ca2+ transport and fluidity. It is anticipated that these experiments will increase our knowledge of the mechanism(s) involved i the action of vitamin D on intestinal calcium transport.

我们实验室的先前研究表明，维生素D-剥夺 在11至18周内导致脂质流动性发生变化和 磷脂酰胆碱（PC）和 大鼠近端小肠刷的磷脂酰乙醇胺（PR） 边界膜。 此外，管理1,25（OH）2d3至D-Deprived 动物迅速（1-2 h）纠正了这些膜的改变 在最早可检测到的透射Ca2+的刺激之前 通过这种激素运输）（5小时）。 这些观察导致我们 假设这些维生素D诱导的膜变化是 负责这种激素的作用和Ca2+运输。 基于这些先前的发现，本提案的总体目标 是确定这些维生素D诱导的刷子膜是否 改变确实是其CA2+运输效应的原因。 到 实现这一目标，计划了一组实验。 首先，断奶 雄性 - 威斯塔尔大鼠将被剥夺饮食和轻度来源 维生素D 14周（A组）。 年龄匹配的饮食D-重复大鼠 将用作控制（B组）。每个组的大鼠将被治疗 分别使用维生素D或媒介物的类似物。 2-5小时后 将牺牲大鼠，并分离出刷膜膜囊泡。 这些准备工作将进行检查并在其上进行比较： 1）脂质流动性； 2）脂质组成，包括单个分子 PC ND PE的种类； 3）CA2+运输； 4）各种酶促 活动。一旦完成这些研究，膜就会 由动物I组制备A组A和B，并在体外治疗 非特异性脂质转移蛋白与合成脂质体一起 为了用PC的特定分子种类丰富这些膜 和/或PE在较早的研究中发现已改变（请参见上文）。 后 治疗，将分析两组的膜囊泡，并 在其脂质成分，Ca2+运输和 流动性。 预计这些实验将增加我们的 了解涉及维生素D的机制的知识 肠钙转运。