(A) Semi-quantitative analysis by RT-PCR of (A) vdr and (B) cyp24a1 gene expression during the course of regeneration, relative to the expression of the house keeping gene, ef1 α. Mat - mature, uninjured limb tissue; EB/MB - early to mid bud stage blastema tissue; LB – late bud stage blastema tissue; TL – tiny limb tissue; p < 0.05 (one way Anova; Tukey post hoc test relative to mature, uninjured tissue; N = 3). (C) Semi-quantitative analysis by RT-PCR of cyp24a1 revealed a significant increase in the expression of this gene in early bud stage blastema tissue in response to Doxercalciferol treatment (10mg/kg; Dox EB); p < 0.05 (t-test, N = 3). Error bars represent standard error of the mean. (D) Representative images of vehicle (top) and Doxercalciferol treated (10mg/kg, bottom) axolotl tail flaps. Doxcercaliferol treatment resulted in aberrant structures (red arrow) in the tail flap.