Immunohistochemical analysis performed by Sullivan et al. (23) with alloxan-induced diabetic rabbits resulted in a significant increase in ETB after 6 months of diabetes and a non-significant increase of ETA diffused by the corpora cavernosa in the microvasculature located at the edge of the cavernosum corpus and tunica albuginea. The gene discussed is EDNRB; the disease is diabetes mellitus.