Are Leydig cells of neural origin? Substance P-like immunoreactivity in human testicular tissue

Using the immunocytochemical peroxidase-antiperoxidase method we observed strong and selective staining of Leydig cells after incubation of human testicular tissue with an antiserum against substance P and a slightly weaker immunoreactivity against methionine-enkephalin. These results indicate that the embryologic origin of Leydig cells may require reconsideration and also offer a new perspective for research upon the local control mechanisms of spermatogenesis.