人乳非蛋白氮成分：早期哺乳期游离氨基酸和尿素的变化模式

Human milk nonprotein nitrogen components: changing patterns of free amino acids and urea in the course of early lactation.

作者信息

Harzer G, Franzke V, Bindels J G

出版信息

Am J Clin Nutr. 1984 Aug;40(2):303-9. doi: 10.1093/ajcn/40.2.303.

DOI:10.1093/ajcn/40.2.303

Abstract

Free amino acids and urea were analyzed in 78 human milk samples obtained during the first 5 wk of lactation from 10 mothers delivering at term. Significant differences (p less than 0.05) in the concentrations between colostral and mature milk were found for glutamic acid, glutamine, alanine, glycine, cystine, and phosphoethanolamine which increased, and with serine, phosphoserine, aspartic acid + asparagine, arginine, lysine, isoleucine, phenylalanine, proline, methionine, tryptophan, and beta-alanine which decreased. Some of these changes occurred within the first 5 days of lactation, so that differences between transitional and mature milk became negligible (glutamic acid, alanine, and serine, aspartic acid + asparagine, lysine, isoleucine, methionine, tryptophan, respectively). No significant differences between any of the three stages of lactation were found regarding the concentrations of total free amino acids, urea, taurine, threonine, valine, leucine, histidine, and tyrosine. Possible relevances for free amino acids, including nonprotein ones, in human milk are discussed.

摘要

对10名足月分娩母亲在哺乳期前5周采集的78份母乳样本中的游离氨基酸和尿素进行了分析。初乳和成熟乳中谷氨酸、谷氨酰胺、丙氨酸、甘氨酸、胱氨酸和磷酸乙醇胺的浓度存在显著差异（p<0.05），这些物质的浓度升高；而丝氨酸、磷酸丝氨酸、天冬氨酸+天冬酰胺、精氨酸、赖氨酸、异亮氨酸、苯丙氨酸、脯氨酸、蛋氨酸、色氨酸和β-丙氨酸的浓度降低。其中一些变化发生在哺乳期的前5天内，因此过渡乳和成熟乳之间的差异变得微不足道（分别为谷氨酸、丙氨酸和丝氨酸、天冬氨酸+天冬酰胺、赖氨酸、异亮氨酸、蛋氨酸、色氨酸）。在哺乳期的三个阶段中，总游离氨基酸、尿素、牛磺酸、苏氨酸、缬氨酸、亮氨酸、组氨酸和酪氨酸的浓度均未发现显著差异。本文讨论了母乳中游离氨基酸（包括非蛋白质氨基酸）的潜在相关性。