STUDIES ON TESTICULAR FUNCTION

Report 4. Studies on DNA Synthesizing Capacity of Germinal Cell, Especially Spermatogenic Activity Index in Hypospermatogenesis

Abstract

The DNA synthesizing capacity of seminiferous epithelium is a reliable index for estimating the cellular dynamics in spermatogenesis. This DNA synthesizing capacity was investigated by ³H-thymidine corporated into testicular tissue cultured by Trowell's method. Tritium-labeled germinal cells were limited in spermatogonia and preleptotene spermatocytes.
The average value of Tritium-labeled germinal cell counts per tubule in each case was named as spermatogenic activity index.
1) Spermatogenic activity index in normal mature testes indicated the intense DNA synthesizing capacity (11.35, 9.47 and 6.00).
2) In the cases of hypospermatogenesis, spermatogenic activity index was reduced in proportion to the grade of its severity.
3) Significant correlation between sperm count and spermatogenic activity index was found (r=0.63, p<0.05), and relationship between spermatogenic activity index and germinal cell index had also high coefficiency as 0.45 (p<0.01).
4) However, in the cases of more than 50 year-old men, significant correlation was not observed between spermatogenic activity index and germinal cell index (r=0.37, p<0.05).
In high aged men, spermatogenic activity index may be reduced, even if germinal cell index was maintained at a relatively high value.