Branching morphogenesis in the fetal mouse submandibular gland is codependent on growth factors and extracellular matrix.

Branching morphogenesis (BrM) is a basic developmental process for the for- mation of the lung, kidney, and all exocrine glands, including the salivary glands. This process proceeds as follows. An epithelial downgrowth invaginates into underlying mes- enchyme, and forms a cleft at its distal end, which is the site of dichotomous branching and elongation ; this process of clefting and elongation is repeated many times at the dis- tal ends of the invading epithelium until the desired final extent of branching is reached. The distal ends of the epithelium differentiate into the secretory endpieces, and the elon- gated segments become the ducts. This presentation is a brief historical review of stud- ies on BrM during the development of the submandibular gland (SMG). J. Med. Invest. 56 Suppl. : 228-233, December, 2009