The Catabolic Effects of Prolonged Inactivity and Acute Hypercortisolemia Are Offset by Dietary Supplementation

We compared the anabolic stimulus provided by an essential amino acid and carbohydrate (AA/CHO) supplement to a mixed clinical meal during bed rest (BR) and episodic hypercortisolemia (∼24 μg·dl−1). In the experimental (EXP; n = 7) and control (CON; n = 6) groups, femoral arteriovenous blood samples and vastus lateralis biopsy samples were obtained during a primed constant infusion of l-[ring-2H5]phenylalanine and a 14-h infusion of hydrocortisone sodium succinate (60 μg·kg·h−1) before (pre-BR) and after (post-BR) 28 d of BR. Muscle protein kinetics were calculated during the postabsorptive state, for 2.5 h after ingestion of a meal and for 2.5 h after ingestion of an AA/CHO supplement (EXP) or placebo (CON). Postabsorptive net phenylalanine balance values were as follows: EXP, −35.14 ± 2.93, and CON, −32.60 ± 6.65 (pre-BR); and EXP, −32.91 ± 5.67, and CON, −30.43 ± 6.28 nmol phe·ml−1·100 ml leg volume−1 (post-BR). After AA/CHO supplementation, net phenylalanine balance improved to 33.51 ± 8.06 (pre-BR) a...