Epithelial progenitor cells in the rat trachea.

Highly pure populations of basal and secretory cells from the rat trachea have been inoculated into denuded tracheal grafts to determine the differentiation pathways of these two cell types. The basal cell inoculum resulted in an epithelium comprised of only basal and ciliated cells, while the secretory cell inoculum gave rise to an epithelium comprised of secretory, basal, and ciliated cells. These results show that, in the rat trachea, the secretory cell is the major progenitorial cell type and the basal cell has only limited progenitorial capacity.