| Abstract: | The change in cell surface adhesive specificity previously shown to occur between day 7 and 8 of development in the chick optic tectum ]Gottlieb et al. (1974), Proc. Nat. Acad. Sci. USA 71, 1800-1802] can be induced in rotating cultures of tectal cells by the addition of 10(-7) M mouse submaxillary gland nerve growth factor. Insulin, proinsulin, dexamethasone, and performic-acid-oxidized nerve growth factor are individually inactive in this system, but nerve growth factor in which the three tryptophan residues/subunit have been oxidized with N-bromosuccinimide is active. Thus, the specificity of this system for nerve growth factor is different than that observed with embryonic dorsal root or sympathetic ganglia, where the oxidized tryptophan derivative is inactive in stimulating neurite production. It is possible that in this system nerve growth factor serves as an analog of another specific trophic factor, presumably structurally related to nerve growth factor, may be active at much lower concentrations. |
