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Periodontal ligament fibroblasts, preosteoblasts, and prechondrocytes express receptors for epidermal growth factor in vivo: a comparative radioautographic study.

Radioiodinated mouse epidermal growth factor (EGF) was used in light and electron microscopic radioautographic studies of the binding of EGF to various cells of young rats. High levels of bound EGF were noted on periodontal ligament fibroblasts, preosteoblasts, and prechondrocytes. Fibroblast in the oral mucosa, tail subepithelial connective tissue, and tail tendon demonstrated much lower levels of binding. Ultrastructural radioautography revealed that silver grains, indicative of radioiodinated EGF, were positioned adjacent to or over the plasma membranes of the cells at 5 minutes after injection of the growth factor. The significance of the high level of EGF receptors on periodontal ligament fibroblasts, comparable to the number observed on preosteocytes and prechondrocytes, is discussed in terms of the possible progenitor role of periodontal ligament fibroblasts for adjacent hard tissue-producing cells.