Basic fibroblast growth factor can induce exclusively neural tissue in Triturus ectoderm explants

Ectoderm was isolated from early gastrulae of Triturus alpestris and induced with recombinant basic fibroblast growth factor (b-FGF). Neural tissue differentiated in about 38% of the explants which were induced by 2,5 μg/ml FGF. These explants do not contain other tissues, or contain only small amounts of mesenchyme and melanophores which are probably derived from induced neural crest. It is therefore unlikely that these neural tissues are secondarily induced. The other explants contain predominantly blastema tissue, endothelium/ mesothelium, small amounts of skeletal muscle and, rarely, notochord besides neural tissues. The mitotic rate was enhanced in about 20% of the induced explants. Possible mechanisms for the unexpected neural-inducing activity of b-FGF in Triturus ectoderm are discussed.