富含亮氨酸的乳清蛋白增加亮氨酸的可利用性，可改善衰老大鼠的餐后肌肉蛋白质合成。

Increased availability of leucine with leucine-rich whey proteins improves postprandial muscle protein synthesis in aging rats.

作者信息

Rieu Isabelle, Balage Michèle, Sornet Claire, Debras Elisabeth, Ripes Sandrine, Rochon-Bonhomme Cécile, Pouyet Corinne, Grizard Jean, Dardevet Dominique

机构信息

Unité de Nutrition Humaine, UMR 1019, Institut National de la Recherche Agronomique-Centre de Recherche en Nutrition Humaine d'Auvergne, Saint Genès Champanelle, France.

出版信息

Nutrition. 2007 Apr;23(4):323-31. doi: 10.1016/j.nut.2006.12.013. Epub 2007 Mar 23.

DOI:10.1016/j.nut.2006.12.013

PMID:17367997

Abstract

OBJECTIVE

We previously found that aging was characterized by a decreased sensitivity of muscle protein synthesis to leucine and that a free leucine-supplemented diet corrected this defect in old rats and elderly humans. The present experiment was undertaken to evaluate the efficiency of selected leucine-rich proteins to stimulate postprandial muscle protein synthesis in old rats to optimize nutritional protein support in the elderly.

METHODS

Sixty rats (22 mo old) received an experimental meal for the first hour of feeding and a standard diet for the rest of the day for 30 d. Experimental meals contained milk proteins that differed in leucine content: beta-lactoglobulin (14.5% leucine), Prolacta (13.4%), alpha-lactalbumin (10.9%), and casein (10%). As a control, a fifth group was added that received herring flour protein (7.3% leucine). Muscle protein synthesis was determined in vivo in the postprandial state at the end of the 30-d nutritional period using the flooding dose method (1-(13)C phenylalanine).

RESULTS

Leucine intake and plasma leucine concentrations were significantly increased in rats fed meals containing the leucine-rich proteins (i.e., beta-lactoglobulin and Prolacta). As previously observed with free leucine-supplemented meals, postprandial muscle protein synthesis was significantly improved in rats fed the meals containing the leucine-rich proteins. Interestingly, the beneficial effect was maintained after the 30-d supplementation.

CONCLUSION

The results indicated that leucine-rich proteins were efficient in improving muscle protein synthesis in old rats. Thus, nutritional supplements containing such proteins may be efficient in preventing sarcopenia in the elderly and would represent a safe and optimized nutritional strategy. However, further experiments are necessary to determine the duration of such nutritional support to obtain a significant protein gain in muscle.

摘要

目的

我们之前发现衰老的特征是肌肉蛋白质合成对亮氨酸的敏感性降低，并且补充游离亮氨酸的饮食可纠正老年大鼠和老年人的这一缺陷。本实验旨在评估所选富含亮氨酸的蛋白质刺激老年大鼠餐后肌肉蛋白质合成的效率，以优化老年人的营养蛋白质支持。

方法

60只大鼠（22月龄）在进食的第1小时接受实验餐，其余时间接受标准饮食，持续30天。实验餐含有亮氨酸含量不同的乳蛋白：β-乳球蛋白（亮氨酸含量14.5%）、Prolacta（13.4%）、α-乳白蛋白（10.9%）和酪蛋白（10%）。作为对照，增加了第五组，给予鲱鱼粉蛋白（亮氨酸含量7.3%）。在30天营养期结束时，使用灌流剂量法（1-（13）C苯丙氨酸）在餐后状态下体内测定肌肉蛋白质合成。