ESTIMATION OF THE DURATION OF THE CYCLE OF THE SEMINIFEROUS EPITHELIUM IN THE NONHUMAN PRIMATE MACACA-MULATTA USING THE 5-BROMODEOXYURIDINETECHNIQUE

A comparatively low yield of germ cells has been reported for the sper matogenic process in primates. Kinetic studies of spermatogenesis and the spermatogenic cycle are needed to investigate this phenomenon but require the application of radioactively labelled compounds or it-radi ation. We have therefore investigated the suitability of a non-radioac tive approach, viz., administration of 5-bromodeoxyuridine, for the de termination of the kinetics of the spermatogenic cycle in a non-human primate, the rhesus monkey (Macaca mulatta). Four adult in-season anim als received a bolus of 33 mg/kg 5-bromodeoxyuridine, one testis from each monkey was removed 3 h later and the other testis after 10 days a nd 11 h. Tissue was fixed in Bouin's solution and embedded in Paraplas t. 5-Bromodeoxyuridine was localized by immunogold-silver staining wit h a monoclonal antibody. PAS-hematoxylin counterstaining was used for spermatogenic stage identification. At 3 h, the leptotene and zygotene spermatocytes in stages VII-IX were the most advanced 5-bromodeoxyuri dine-positive cells. At 10 days 11h, the label had advanced and pachyt ene spermatocytes in stages VI-IX contained 5-bromodeoxyuridine. The d uration of the spermatogenic cycle was 10.42+/-0.07 days (range: 10.25 -10.62 days). Peritubular cells and interstitial cells were rarely 5-b romodeoxyuridine-positive, and Sertoli cells were consistently negativ e for 5-bromodeoxyuridine. Importantly, our kinetic data closely resem ble those obtained by means of the application of irradiation for this macaque species. We conclude that administration of 5-bromodeoxyuridi ne represents a non-radioactive reliable approach for studying kinetic aspects of the spermatogenic process in primates.