BEEF INGESTION AND MUSCLE PROTEIN METABOLISM

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。许多人失去肌肉质量和力量，因为他们变老。可能导致这种损失的因素之一是饮食的变化。具体来说，老年人可能没有摄入足够的膳食蛋白质，或者他们摄入的蛋白质可能无法有效地被肌肉组织吸收。以前的研究已经检查了蛋白质补充剂和氨基酸对蛋白质合成和肌肉生长的影响，但是缺乏检查膳食蛋白质的常见来源（即，牛肉）对肌肉蛋白质合成的影响。 本研究的目的是测量年轻人和老年人摄入4盎司瘦牛肉后血浆氨基酸浓度和肌肉蛋白质合成的变化。 我们将研究20名健康男性和女性志愿者，年龄在20 - 50岁（年轻人）和60 - 85岁（老年人）之间。我们将使用已建立的技术，包括稳定同位素示踪方法，血液采样和肌肉活检，以测量血浆激素和氨基酸浓度和骨骼肌合成的变化。 这个项目将研究肌肉蛋白质合成的变化，以应对一个共同的饮食蛋白质来源。这项研究将解决一些机制，有助于在衰老过程中的肌肉损失。特别是，该项目将直接影响作为日常饮食一部分摄入的蛋白质的质量和数量。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Many individuals lose muscle mass and strength as they get older. One of the factors that may contribute to this loss is changes in the diet. Specifically, elderly individuals may not eat sufficient dietary protein or the protein they do eat may not be as efficiently assimilated into muscle tissue. Previous studies have examined the effect of protein supplements and amino acids on protein synthesis and muscle growth, but there is a lack of data examining the effect of common sources of dietary protein (i.e., beef) on muscle protein synthesis. The goal of this study is to measure changes in plasma concentrations of amino acids and muscle protein synthesis in young and elderly individuals following ingestion of 4 oz of lean beef. We will study a total of 20 healthy male and female volunteers between the ages of 20 and 50 (young) and 60 and 85 (elderly). We will use established techniques including stable isotope tracer methodology, blood sampling and muscle biopsies to measure changes in plasma hormone and amino acid concentrations and skeletal muscle synthesis. This project will examine changes in muscle protein synthesis in response to a common source of dietary protein. This study will address a number of the mechanisms contributing to muscle loss during aging. In particular, this project will have direct implications for both the quality and quantity of protein ingested as part of a daily diet.