N-acetyl endorphin in rat spermatogonia and primary spermatocytes.

In previous reports modest levels of f-endorphin have been found by radioimmunoassay in rat testis, and localized by immunofluorescence to the interstitial cells. We have confirmed these previous reports and extended them by showing that the majority of testicular endorphins are acetylated forms, N- acetyl y-endorphin, N-acetyl a-endorphin, and N-acetyl jB- endorphin, 27. In addition, N-acetylated endorphins are not found in interstitial cells, but are confined to spermatogonia and primary spermatocytes. that, in contrast with f3-EP which appears confined to interstitial cells, N-Ac-EPs are found in spermatogonia and primary spermatocytes.