Nutrient sensing anabolic pathway is increased in the elderly following chronic dietary leucine supplementation

Abstract

Leucine has been shown to act as a key regulator of the nutrient sensing anabolic pathway. Acute administration of leucine affects the phosphorylation status of several proteins involved in translation initiation that are regulated by the mTOR pathway. We conducted a 14 day pilot study in which we supplemented regular daily meals of community dwelling elders (n=8, 63–76 yrs) with a small amount of leucine (4 g per meal; 3 meals per day; days 2–13). On days 1 and 14, muscle biopsies were obtained in the post‐absorptive state to determine leucine‐induced modulation of the mTOR signaling pathway. After 14 days of leucine supplementation, there was a trend toward increased phosphorylation of mTOR (P=0.06). In addition, the phosphorylation of the downstream effectors 4E‐BP1 (P=0.03) and p70S6K (P=0.08) were increased. These data suggest that a provision of leucine supplementation facilitates an adaptive change in components of the mTOR signaling pathway in aging human muscle.Grant Funding Source: UTMB Claude D. Pepper Older Americans Independence Center # P30 AG024832 (to D. Paddon‐Jones) and NIH/NCI grant 5R01 CA127971 (to M. Sheffield‐Moore).