Cell division and ribonucleic acid synthesis during the initiation of limb regeneration in larval axolotls (Ambystoma mexicanum)

Mitotic activity and RNA synthesis were examined in normal regenerating limbs and denervated non‐regenerating limbs of larval axolotls during the first six days after amputation. H 3 ‐uridine incorporation into RNA was measured by autoradiography of deoxyribonuclease treated sections. Grain counts indicated a significant increase in RNA synthesis in both normal and denervated limbs through the six‐day time period but a greater increase was seen in normal limbs. The Mitotic Index increased significantly in normal limbs on the fifth day postamputation. In contrast, no increase in M.I. was observed in denervated limbs.