Dietary Whey Protein Hydrolysates Increase Skeletal Muscle Glycogen Levels via Activation of Glycogen Synthase in Mice

• Published in: Journal of agricultural and food chemistry 2012-11, Vol.60 (45), p.11403-11408
• Main Authors: Kanda, Atsushi, Morifuji, Masashi, Fukasawa, Tomoyuki, Koga, Jinichiro, Kanegae, Minoru, Kawanaka, Kentaro, Higuchi, Mitsuru
• Format: Article
• Language: English
• Subjects: amino acids; Animals; Biological and medical sciences; Dietary Proteins - metabolism; Enzyme Activation; experimental diets; Food industries; Fundamental and applied biological sciences. Psychology; glycogen; Glycogen - biosynthesis; Glycogen Synthase - metabolism; Male; Mice; Milk and cheese industries. Ice creams; Milk Proteins - metabolism; Muscle, Skeletal - metabolism; protein hydrolysates; Protein Hydrolysates - metabolism; skeletal muscle; whey protein; Whey Proteins
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf302277a

Previously, we have shown that consuming carbohydrate plus whey protein hydrolysates (WPHs) replenished muscle glycogen after exercise more effectively than consuming intact whey protein or branched-chain amino acids (BCAAs). The mechanism leading to superior glycogen replenishment after consuming WPH is unclear. In this 5 week intervention, ddY mice were fed experimental diets containing WPH, a mixture of whey amino acids (WAAs), or casein (control). After the intervention, gastrocnemius muscle glycogen levels were significantly higher in the WPH group (4.35 mg/g) than in the WAA (3.15 mg/g) or control (2.51 mg/g) groups. In addition, total glycogen synthase (GS) protein levels were significantly higher in the WPH group (153%) than in the WAA (89.2%) or control groups, and phosphorylated GS levels were significantly decreased in the WPH group (51.4%). These results indicate that dietary WPH may increase the muscle glycogen content through increased GS activity.