The effect of 6-aminonicotinamide on limb development.

The morphological effect of the nicotinamide analogue 6-aminonicotinamide on the development of the embryonic chick limb was studied, with special reference to muscle, cartilage, feather germ formation, and ossification. No evidence was found to support theories of control of differentiation by nicotinamide-like substances, although the effect of nicotinamide analogues has often been quoted as evidence for such theories. However, the effect of 6-AN in shortening the limb provides an opportunity to study the interaction of various tissues in normal growth and development, and the results are used to shed further light on the processes involved in muscle splitting, and feather germ formation.