%0 Journal Article
%T Sexually dimorphic effect of aging on skeletal muscle protein synthesis
%A Gordon I Smith
%A Dominic N Reeds
%A Angela M Hall
%A Kari T Chambers
%A Brian N Finck
%A Bettina Mittendorfer
%J Biology of Sex Differences
%D 2012
%I BioMed Central
%R 10.1186/2042-6410-3-11
%X We measured the skeletal muscle protein fractional synthesis rate (FSR) by using stable isotope-labeled tracer methods during basal postabsorptive conditions and during a hyperaminoacidemic-hyperinsulinemic-euglycemic clamp in eight young men (25¨C45 y), ten young women (25¨C45 y), ten old men (65¨C85 y) and ten old women (65¨C85 y).The basal muscle protein FSR was not different in young and old men (0.040£¿¡À£¿0.004 and 0.043£¿¡À£¿0.005%¡¤h-1, respectively) and combined insulin, glucose and amino acid infusion significantly increased the muscle protein FSR both in young (to 0.063£¿¡À£¿0.006%¡¤h-1) and old (to 0.051£¿¡À£¿0.008%¡¤h-1) men but the increase (0.023£¿¡À£¿0.004 vs. 0.009£¿¡À£¿0.004%¡¤h-1, respectively) was ~60% less in the old men (P£¿=£¿0.03). In contrast, the basal muscle protein FSR was ~30% greater in old than young women (0.060£¿¡À£¿0.003 vs. 0.046£¿¡À£¿0.004%¡¤h-1, respectively; P£¿<£¿0.05) and combined insulin, glucose and amino acid infusion significantly increased the muscle protein FSR in young (P£¿<£¿0.01) but not in old women (P£¿=£¿0.10) so that the FSR was not different between young and old women during the clamp (0.074£¿¡À£¿0.006%¡¤h-1 vs. 0.072£¿¡À£¿0.006%¡¤h-1, respectively).There is sexual dimorphism in the age-related changes in muscle protein synthesis and thus the metabolic processes responsible for the age-related decline in muscle mass.
%K Muscle protein turnover
%K Aging
%K Sarcopenia
%K Amino acid
%U http://www.bsd-journal.com/content/3/1/11/abstract