[Spermatogenesis in old age--nuclear DNA determination by flow cytophotometry in testicular samples of older men for the quantification of spermatogenesis].

The flow cytometric determination of the nuclear DNA content of testicular samples permits a fast and reliable quantification of spermatogenesis. 70 testicular samples from men over 50 years of age were analysed with this method. 60% of the samples showed a distinct reduction of spermatogenesis. Only three men showed a nonreduced spermatogenesis in both testes. Comparing the results of the measurements of both testes, in nearly half of the testes pairs a reduction of the germ cell number below two thirds of the better side was striking. In one patient, a Leydig cell tumor was detected by chance by an aneuploidy.