Fig. 2.

The effect of testosterone administration and co-incubations of flutamide (F) and Picropodophyllin (PPP) on myotube formation and hypertrophy. Testosterone was rendered inactive in its ability to promote differentiation in CON and PD muscle cells following its co-incubation with AR inhibitor flutamide, resulting in no quantifiable myotubes being observed at any time point. a In CON cells, testosterone significantly increased myotube diameter at 72 h and 7 days exposure. The co-incubation of testosterone with Picropodophyllin did not abrogate testosterones increases in myotube diameter at either time point (*P ≤ 0.05). b A similar trend occurred in PD myoblasts with testosterone treatment significantly increasing myotube diameter compared to un-treated cells (*P ≤ 0.05). The observed increases in testosterone induced hypertrophy continued at 7 days treatment (**P ≤ 0.05). The addition of PPP had no effect on altering the observed increases in hypertrophy at either time point in PD myoblasts. c The addition of PPP alone significantly reduced myotube number in CON myoblasts after 72 h (*P ≤ 0.05). Testosterone significantly increased myotube number after 7 days exposure (**P ≤ 0.001) in CON myoblasts, but the addition of PPP somewhat attenuated this increase. d Significant difference (*P < 0.05) between PD treatments at 72 h and 7 days for myotube number. The myotube number at 7 days in PD myoblasts was increased with the co-incubation of testosterone and PPP compared to untreated and PPP treated cells (**P ≤ 0.001). e, f Testosterone significantly increased the average number of nuclei per myotube in both CON and PD cells after 72 h (*P < 0.05) and 7 days (**P < 0.05) compared to untreated cells. The co-incubation of picropdophyllin with testosterone did not negate the observed increases in nuclei per myotube in either cell type after 7 days treatment. Values presented as Mean ± SD