Immunocytochemical demonstration of substance P in hamster Leydig cells during ontogenesis

The cellular localization of substance P immunoreactivity was demonstrated at the light microscopical level in the hamster testis during fetal and postnatal development. A selective immunostaining was observed both of fetal and adult generation of Leydig cells. The comparison of the immunocytochemical findings with the ultrastructural characteristics of Leydig cells provided evidence that Leydig cells besides their androgen-producing capacity also had an neuropeptide producing function. The possible role of substance P in the local paracrine control of gametogenesis was discussed.