Quantitative evaluation of spontaneous and radiation-induced polyploidisation processes in human and murine testes

Flow cytometric analysis of human and murine testicular tissue was performed in order to determine whether cells exist with a DNA content differing from the expected categories 1 c, 2 c and 4 c, and to estimate the frequencies of diploid elongated spermatids. About 1.5 per cent of the murine testicular cells had an 8 c DNA content. In human testis, no 8 c cells were detected. A slight increase of 8 c cells was observed in the murine testis, following irradiation. An average of 1.8 per cent of the elongated spermatids in 10 control mice were diploid. In 12 human testicular biopsies, an average of 4.7 per cent of diploid elongated spermatids was observed among all elongated spermatids in mice. Acute or split-dose exposure, with 15 Gy roentgen rays, to spermatocytes increased the spontaneously occurring level of diploid elongated spermatids 25-fold.