The peptide hormone alpha-melanocyte stimulating hormone (alpha-MSH), accelerates the return of sensitivity to the rat hindpaw after nerve transection. A marked reduction in the recovery time is observed when alpha-MSH is applied locally to the repair site by means of the microporous Accurel polypropylene tube delivery system. The tubes alone have a significant but smaller beneficial effect. These results have implications for the mode of action of neurotrophic melanocortins and suggest a potential means of improving the outcome of surgical nerve repair in the clinic.