FSH stimulates proliferation of murine ES-D3, but not P19 cells. The effect of pituitary hormone on the proliferation of (A) ES-D3 and (B) P19 cells. In the upper line graphs, the values are the percentage of cells on day 0. In the lower bar graphs, the values are normalized to the negative control, which represents 100% of cells on a particular day. For each cell line, the experiment was repeated twice in triplicate with similar results.