Fig. 2

Circulating myostatin and propeptide levels by LC-MS/MS in younger and older women and men. Box plots (25–75 percentile) and whiskers (Tukey method) comparing serum concentrations of a myostatin, b myostatin relative to total body lean mass (TBLM), c propeptide, and d propeptide relative to TBLM between younger women (YW), older women (OW), and sarcopenic older women (SOW). Comparisons of circulating concentrations of absolute and relative concentrations of myostatin and propeptide between corresponding groups of men are also illustrated (e-h). *, **, and *** denote p < 0.05, 0.01, and 0.001, respectively, compared to the younger group except when denoted with a bracket