Fig. 3. Effects of cyclic stretching at different time points during the induction period on adipocyte differentiation of 3T3-L1 cells. (A) The protocols of cyclic stretching at different time points during the induction period. Briefly, the 3T3-L1 cells, treated with induction medium containing DEX, MIX, INS and FBS (DEX/MIX/INS), were subjected to cyclic stretching (at 130%, 1 Hz) for the entire period (0-45 hours; S₄₅), for the first 15-hour period (early phase, 0-15 hours; S_E15) and for the final 15-hour period (late phase, 30-45 hours; S_L15) of the induction period of 45 hours. R₄₅, without stretching for the entire period. (B) Relative GPDH activity. (C) Triglyceride content of post-maturation 3T3-L1 cells with (grey) or without (black) cyclic stretching at different time points during the induction period (n=4; ^*P<0.05; ^**P<0.01). (D) The total RNA of 3T3-L1 cells at the end of the induction period was subjected to quantitative RT-PCR and blots of the PCR products were hybridized with DIG-labelled cDNA probes corresponding to each target mRNA. (n=5; ^**P<0.01).