Ghrelin peptides effects on sarcopenia-dependent atrophy. (A) Atrogin-1 (Fbxo32) expression in gastrocnemius (GAS) and tibialis anterior (TA) of 3-month old (young) and 24-month old (old) mice determined by real-time RT-PCR. In GAS, young mice: WT = 4, Tg = 4, Ghrl KO = 4; old mice: WT = 4, Tg = 3, Ghrl KO = 4. In TA, young mice: WT = 4, Tg = 3, Ghrl KO = 4; old mice: WT = 8, Tg = 6, Ghrl KO = 5. (B) Cathepsin-L (Ctsl), (C) Bnip-3 (Bnip3), and (D) IGF-1 (Igf1) expression in gastrocnemius of 3-month old (young) and 24-month old (old) mice determined by real-time RT-PCR. Young mice: WT = 3, Tg = 3, Ghrl KO = 4; old mice: WT = 7, Tg = 9, Ghrl KO = 5. (E) Cross-sectional area (CSA) frequency distribution of myofibers in GAS of old WT, Tg, and Ghrl KO mice. WT= 4, Tg= 3, Ghrl KO= 5. The shadowed area of the graph represents the section of statistically significant differences among curves. Data are presented as mean ± SEM. *p<0.05 and **p<0.01 old vs. young; $p<0.05 and $$p<0.01 Tg and Ghrl KO vs. WT.