Keratinocyte substrate adhesion is magnesium-dependent and calcium-independent.

Primary cell cultures were prepared from guinea pig epidermis and six days old mice kidneys and hearts. Along with subcultures of Hep cells, plating experiments were performed using media devoid of bivalent cations containing dialzyed fetal calf serum. Upon stepwise supplementation with either calcium ++ or magnesium ++, keratinocytes displayed a unique dependency on magnesium ++ for cell attachment, whereas all other cell types could make use of either of these ions. Melanocytes, being a minority component of the epidermal cell population, do not conform to the predilection of keratinocytes for magnesium ++. Epidermal cell cultures prepared in media containing only calcium ++, therefore, result in pure melanocyte cultures.