Immunohistochemical localization of beta-endorphin in hyperplastic interstitial tissue of the human testis.

The immunohistochemical localization of beta-endorphin in the normal testis (two patients) and in the pathologic testis (two cases of Sertoli Cell Only Syndrome, two cases of Klinefelter Syndrome, two cases of post-orchitis tubular sclero-hialinosis) was investigated. No beta-endorphin immunostaining was detected in the normal testis, while positive beta-endorphin immunostaining has been observed in pathologic tissues. These results indicate that, as in animals, beta-endorphin is present in human Leydig cells and may play a local role in regulating male reproductive function.