Figure 2. Dose dependent effect of 1 and 2 on protein synthesis (A) and protein degradation (B) in L6 rat myotubes.

(A) Cells were incubated for 4 h with [³H]-phenylalanine and treated in triplicate with vehicle (0.1% ethanol), 6.5 nM of IGF-1 as a positive control, or test compound (0.3–30 μM), and protein synthesis was measured as incorporation of [³H]-phenylalanine into protein normalized by total protein. (B) Dose-dependent effect of HB on protein degradation was observed in cells labeled overnight with [³H]-phenylalanine and subsequently treated for 4 h with vehicle (0.1% ethanol), 10 nM of insulin as a positive control, or brassinosteroid analogues (0.3–30 μM); then protein degradation was measured as release of acid-soluble [³H]-phenylalanine into media. Results are expressed as the mean ± SEM of determinations performed in triplicate (* P<0.05, ** P<0.01, *** P<0.001 when compared with control by one-way ANOVA and Dunnett’s post-test).