Abstract
Sheets of sensory epithelia were isolated from the utricles of chicks and cultured in serum-free media and in media that contained serum. The proliferation of epithelial supporting cells was assayed using the mitotic tracer bromodeoxyuridine. Similar levels of supporting cell proliferation were observed in epithelia maintained in serum-free and serum-containing media. The results suggest that the vestibular epithelia of birds contain whatever mitogens are necessary for the continued proliferation of epithelial supporting cells.