Branched-chain amino acid-containing dipeptides, identified from whey protein hydrolysates, stimulate glucose uptake rate in L6 myotubes and isolated skeletal muscles

Masashi Morifuji*, Jinichiro Koga, Kentaro Kawanaka, Mitsuru Higuchi

*この研究の対応する著者

研究成果: Article査読

84 被引用数 (Scopus)

抄録

In earlier studies we showed that dietary whey protein increased skeletal muscle and liver glycogen content in exercise-trained rats. However, little is known about whether ingredients of whey protein stimulate skeletal muscle glycogen accumulation. The aim of this study was to identify bioactive peptides in whey protein hydrolysates (WPH) which stimulated glucose uptake and glycogen synthesis rate in skeletal muscles. Branched-chain amino acid (BCAA)-containing dipeptides in WPH were identified using LC/MS/MS. L6 myotubes and isolated epitrochlearis muscles were used for the glucose uptake assays. The myotubes and muscles were incubated with or without 1 mM dipeptides, LY294002 a phosphoinositide 3-kinase (PI3-kinase) inhibitor, or GF102903X an atypical protein kinase C (aPKC) inhibitor, followed by measurement of 2-deoxyglucose uptake. Isolated muscles were incubated for 3 h with or without 1 mM Ile-Leu to determine glycogen synthesis rate. The BCAA-containing dipeptides, Ile-Val, Leu-Val, Val-Leu, Ile-Ile, Leu-Ile, Ile-Leu, and Leu-Leu were detected in the WPH by LC/MS/MS. These dipeptides caused significant stimulation in glucose uptake rate in the L6 myotubes. Ile-Leu, the main component in WPH, also stimulated glucose uptake in isolated skeletal muscles. Stimulation of glucose uptake by Ile-Leu was completely inhibited by treatment with either LY294002, or GF109203X in both L6 cells and isolated muscles. Ile-Leu increased glycogen contents in isolated muscles. These results suggest that BCAA-containing bioactive dipeptides in WPH stimulate glucose uptake in skeletal muscles via the PI3-kinase and aPKC pathways, resulting in increased skeletal muscle glycogen contents.

本文言語English
ページ(範囲)81-86
ページ数6
ジャーナルJournal of Nutritional Science and Vitaminology
55
1
DOI
出版ステータスPublished - 2009

ASJC Scopus subject areas

  • 医学(その他)
  • 栄養および糖尿病

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