Research Paper Volume 11, Issue 24 pp 11922—11936

Suppression of protein degradation by leucine requires its conversion to β-hydroxy-β-methyl butyrate in C2C12 myotubes

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Figure 4. Effects of Leu and HMB on protein degradation, the oxygen consumption rate (OCR), and MyHC I protein expression and immunofluorescence intensity in KICD-transfected C2C12 myotubes. (A) RT-PCR and Western blot analysis of KICD from non-transfected and transfected C2C12 myotubes is shown. (B) Protein degradation rates in the presence of 0.5 mM Leu and 50 μM HMB. (C) The OCR of cells in the presence of 0.5 mM Leu and 50 μM HMB. (D) MyHC I protein expression in the presence of 0.5 mM Leu and 50 μM HMB. (E) MyHC I immunofluorescence intensity in the presence of 0.5 mM Leu and 50 μM HMB. Results are expressed as mean ± SEM. Different letters (a, b, c) indicated significant differences (P < 0.05). CON, control; HMB, β-hydroxy-β-methyl butyrate; KIC, α-ketoisocaproate; Leu, leucine.