Differential calcium requirements for growth of mouse skin epithelial and fibroblast cells

Concentration of extracellular Ca++ optimum for growth of cell types of mesodermal origin have been reported to be up to 100-fold higher than concentrations optimal for epidermal or other epithelial lining cells. In order to examine Ca++ requirements of epithelial v. fibroblastic cells derived from a common tissue source, prior to prolonged culture, freshly isolated mouse epidermal keratinocytes, hair follicle cells and dermal fibroblasts were plated at high density or at clonal density in medium ranging from 0.014 to 1.4 mM Ca++. Epithelial skin cells grew best at Ca++ levels below 0.1 mM while dermal fibroblasts grew best at a Ca++ concentration of 1.4 mM. The epithelial cell types exhibited marked morphologic changes in response to Ca++, while the fibroblasts did not. These results suggest that the variations in Ca++ response between lining epithelium and mesenchymal cells resulted from inherent differences in these cell types, but a mechanism for such differential effects has not yet been defined.