Mitotic activity and nucleic acid precursor incorporation in denervated and innervated limb stumps of axolotl larvae.

Mitotic activity and DNA and RNA precursor incorporation were compared in innervated regenerating limbs and in denervated, non-regenerating limbs on days 8 and 9 post-amputation. Innervated limbs had well-developed cone stage blastemas which showed high cellular mitotic indices and H3-thymidine labeling indices of 0.40-0.50 and H3-uridine labeling indices of 0.50-0.75. In contrast, denervated limbs showed dedifferentiated cells distally under thickened wound epithelia, but essentially no mitotic activity and no blastema formation. These dedifferentiated cells showed lower levels of H3-thymidine (0.10 index) and H3-uridine (0.50) incorporation than regenerating limbs. Labeling indices of wound epithelia are also compared.