['To compare the extent of modulation by various growth factors on clonal growth and differentiation between corneal and stem cell-containing limbal epithelium.', 'A reported serum-free clonal growth assay was used. The mitogenic response was measured by colony forming efficiency, colony size, and bromodeoxyuridine labelling index; the differentiation was assessed by AE-5 monoclonal antibody staining.', "As compared to controls in an insulin-containing basic medium, the addition of epidermal growth factor, acidic fibroblast growth factor, basic fibroblast growth factor, and a high dose of nerve growth factor was mitogenic for both epithelia. Cholera toxin was also mitogenic, but platelet-derived growth factor might not have, and insulin-like growth factor type I lacked an additive mitogenic effect with insulin. The mitogenic effect of epidermal growth factor differed from the others in its dose-dependent down-regulation and in having more migratory cells in epidermal growth factor-stimulated colonies. In contrast to these mitogens, transforming growth factor-beta 1 exhibited a clear inhibitory effect in the controls as well as in epidermal growth factor- or fibroblast growth factor-stimulated cultures. Transforming growth factor-beta 1's inhibitory effect was correlated with strong AE-5 staining, whereas the mitogenic effect of epidermal growth factors, fibroblast growth factors or nerve growth factors was correlated with the presence of negative AE-5 colonies."] Do growth factors modulate clonal growth and differentiation of cultured rabbit limbal and corneal epithelium?