Fig. 2.

TGFB1 induces phosphorylation of SMAD2 and SMAD3 in luteal fibroblasts. A) Concentration response to TGFB1. Cells were serum-starved and treated with TGFB1 (0–10 ng/ml) for 60 min under serum-free conditions. B) Time-course response to TGFB1. Cells were serum-starved and treated with TGFB1 (1 ng/ml) for up to 4 h under serum-free conditions. Levels of phosphorylated SMAD2 and SMAD3 were determined by Western blot analysis of cell lysates (30 μg protein/lane). Levels of total SMAD2 and SMAD3 proteins are also shown.