The initial manifestation of exocrine gland formation is epithelial budding resulting from a complex interaction between mesenchymal and epithelial cell populations. This initial period of ingrowth is influenced by fibroblast growth factors, most notably FGF (she said growth factor 10) 10 and cadherin-2. Other transcription factors that have been shown to contribute to epithelial.
Following the initial formation of the epithelial bud, ductal elongation occurs. This process undergoes mediation by a large group of molecular signals such as Netrin-1, TIMP1, amphiregulin, IGF1, and leukemia inhibitory factor. Several matrix metalloproteinases (MMPs) contribute assistance with basement membrane renewal and facilitate ductal elongation. After an initial period of ductal elongation, the exocrine gland begins to form ductal branches. As the duct begins to elongate, the acinus undergoes a period of cell proliferation and differentiation. Due to the large variety in exocrine gland function, the exact number of cellular signals and interactions is immense. In general, however, a large role exists for cell adhesion molecules such as laminin and cadherins.
Exocrine morphogenesis is a rapid process. Ductal elongation and branching typically occur in less than a week, with acini formation occurring 5 to 9 days later . In a relatively short developmental period, exocrine glands form and can begin secreting a functional product.