ADAPTIVE REGULATION OF NUTRIENT TRANSPORT BY THE GUT

该项目位于营养学和胃肠病学之间的交界处。 它询问肠道的营养吸收机制是如何适应的。 受监管的。 目标集中在三个问题上。1.有哪些模式？ 营养素摄取随饮食变化、怀孕和其他正常情况的变化 以及与疾病相关的疾病？2.导致这些疾病的机制是什么 这些变化？3.这些变化的信号是什么？ 具体目标有四个方面： 1.哪种饮食条件能最大限度地诱导四种主要的 依赖于钠离子的氨基酸转运体？这项研究将指导尝试 分离转运蛋白并了解诱导信号。 2.底物依赖的转运蛋白诱导是否只发生在 分化的隐窝细胞，还是成熟的肠道细胞？ 3.模式、触发信号、功能意义、 机制，以及可能作为消化瓶颈的作用，导致 个体发育过程中的转运蛋白？ 4.实验性糖尿病通过什么机制改变营养吸收 被肠子刺伤？ 主要用于测量示踪剂摄取，肠道形态计量学， 和传送器站点编号。 该项目具有与健康相关的影响：1.饮食作用 氨基酸，不仅作为必需的营养素，而且作为诱导剂 吸收其他营养素；2.血浆改变对健康的影响 因肠道养分摄取改变而导致的营养素水平；3.改变 糖尿病和其他疾病状态下的营养摄取。

This project lies at the interface between nutrition and gastroenterology. It asks how the nutrient uptake mechanisms of the intestine are adaptively regulated. The objectives focus on three questions. 1. What are the patterns of changes in nutrient uptake with diet changes, pregnancy, and other normal and disease-related conditions? 2. What are the mechanisms responsible for these changes? 3. What are the signals for these changes? The specific aims are four-fold: 1. What dietary conditions yield maximal induction of each of the four main Na+-dependent amino acid transporters? This study will guide attempts to isolate transporters and to understand inducing signals. 2. Does substrate-dependent induction of transporters take place only in differentiating crypt cells, or in mature enterocytes as well? 3. What are the patterns, triggering signals, functional significance, mechanisms, and possible role as digestive bottlenecks, for the changes in transporters during ontogenetic development? 4. By what mechanisms does experimental diabetes alter nutrient absorption by the intestine? The main methods to be used measure tracer uptake, intestinal morphometry, and transporter site number. The project has health-related implications for: 1. the dietary role of amino acids, not only as essential nutrients but also as inducers of absorption of other nutrients; 2. health consequences of altered plasma levels of nutrients due to altered intestinal nutrient uptake; 3. altered nutrient uptake in diabetes and other disease states.