Figure 3.

Provisional model depicting some of the key endocrine and paracrine signals that regulate mammary branching morphogenesis. ADAM, a disintegrin and metalloproteinase; AREG, amphiregulin; EGFR, epidermal growth factor receptor; ER, estrogen receptor; FGF, fibroblast growth factor; FGFR, FGF receptor; GH, growth hormone; GHR, GH receptor; IGF, insulin-like growth factor; IGF1R, IGF-1 receptor; IGFBPs, IGF-binding proteins; MMP, matrix metalloproteinase; TEB, terminal end bud; TIMP, tissue inhibitor of metalloproteinases.