Figure 3
Exogenous TGF-β1 pulses induced autocrine TGF-β1 production. Active TGF-β1 in single and double pulses was elevated in culture medium only 24 h after (a) 4 h and (b) 2 × 4 h TGF-β1 pulse(s). Acidic activation of latent TGF-β1 generated increased TGF-β1 levels at all time points. *P <0.05 (solid line) versus respective untreated controls for active TGF-β1 comparison. *P <0.05 (dotted lines) versus respective untreated controls for latent TGF-β1 comparison. Data are represented as mean ± SD, calculated from four independent studies in triplicate, and expressed as fold changes over respective controls. SD, standard deviation; TGF-β1 transforming growth factor-β1.