BEEF INGESTION AND MUSCLE PROTEIN METABOLISM

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。随着年龄的增长，许多人的肌肉质量和力量都会下降。其中一个可能导致这种损失的因素是饮食的改变。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吸收到肌肉组织中。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，但缺乏检查常见膳食蛋白质来源（即牛肉）对肌肉蛋白质合成的影响的数据。这项研究的目的是测量年轻人和老年人在摄入4盎司瘦牛肉后血浆氨基酸浓度和肌肉蛋白合成的变化。我们将研究20名健康的男性和女性志愿者，年龄在20 - 50岁（年轻人）和60 - 85岁（老年人）之间。我们将使用成熟的技术，包括稳定同位素示踪方法，血液采样和肌肉活检来测量血浆激素和氨基酸浓度以及骨骼肌合成的变化。该项目将研究肌肉蛋白质合成对一种常见膳食蛋白质来源的反应。这项研究将解决在衰老过程中导致肌肉损失的一些机制。特别是，该项目将对日常饮食中摄入的蛋白质的质量和数量产生直接影响。

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.