ANDROGENIC REGULATION OF ENZYMES INVOLVED IN DNA-SYNTHESIS IN EPIDIDYMIS OF YOUNG-RATS

In the epididymis of young rats, activities of DNA polymerases alpha, beta and gamma and DNA topoisomerase I decreased after castration. DNA polymerase alpha and gamma increased with androgen administration and activity reached 81.3% and 78.0%, respectively, of the activity in the sham-operated group on day 21. Activity of DNA polymerase beta remained at the activity of day 7 during androgen administration and was almost the same as that in the sham-operated group on day 21. DNA topoisomerase I activity showed a slight increase with androgen administration and reached 50.3 % of that in the sham-operated group. The activities of these enzymes were not fully restored to those in the sham-operated group. These results indicate that in young rats activities of epididymal DNA polymerase alpha and gamma and DNA topoisomerase I are partially, and that of DNA polymerase beta wholly, dependent on androgens and may provide a means of investigating the regulation of epididymal cell proliferation.