Proliferation of adipose stromal vascular cells. A and B, Proliferation rate of stromal vascular cells from both adipose tissues (inguinal WAT and BAT) was estimated by quantifying cell number using the CellTiter 96 AQ 1 solution assay. Cells were treated ± LR3-IGF1 (n = 12, P ≤ .05), which does not interact with IGF binding proteins, and in the presence of serum. Significant differences within each time period are indicated by different letters whereas the same letters indicate no difference. C and D, Cells were also treated with LR3-IGF1, recombinant myostatin or both for 24 hours after a prolonged (16 h) serum starvation to increase IGF-1 sensitivity (n = 8/group, P ≤ .05). Significant differences among wild-type (WT) or mstn−/− (KO) cells are indicated separately by different letters (eg, capital for WT).