Ciliated and secretory epidermis produced from embryonic mammalian skin in organ culture by vitamin A.

When skin from the upper lip of 12-day embryonic mice was grown for ten days in organ culture with 5.7 mug retinol added per ml of biological medium, keratinization was suppressed and a ciliated and secretory epithelium was produced. Ultrastructural features of this epithelium are described. At this very early stage mouse epidermis is thus similar of chick epidermis in its ability to undergo radical metaplasia in response to vitamin A.