Fujisawa M, Matsumoto O, Kamidono S, Hirose F, Kojima K, Yoshida S
Department of Urology, Kobe University School of Medicine, Japan.
J Reprod Fertil. 1988 Sep;84(1):123-30. doi: 10.1530/jrf.0.0840123.
The activities of DNA polymerase alpha (EC 2.7.7.7) and topoisomerase I did not fluctuate up to 7 days after surgery to induce cryptorchidism and showed no significant difference from those in control testes (sham-operated). In contrast, the activity of DNA polymerase beta decreased by 43% at 5 days (P less than 0.01) and by 47% at 7 days (P less than 0.001). The activity of DNA polymerase gamma also decreased by 46% at 3 days (P less than 0.02) and by 78% at 7 days (P less than 0.01) after surgery. The amount of mRNA for DNA polymerase beta decreased in parallel with enzyme activity. Since the sensitivity to heat inactivation of testicular DNA polymerase beta was exactly the same as that from liver, the decrease in DNA polymerase beta activity may be, at least in part, due to reduced biosynthesis of enzyme protein. The morphological changes in cryptorchid testes suggested that the decrease in DNA polymerase beta and gamma activities might be related to the deleterious effects of elevated temperature on spermatogenesis.
诱导隐睾症手术后长达7天，DNA聚合酶α（EC 2.7.7.7）和拓扑异构酶I的活性没有波动，与对照睾丸（假手术）相比无显著差异。相反，DNA聚合酶β的活性在术后5天下降了43%（P<0.01），在7天下降了47%（P<0.001）。DNA聚合酶γ的活性在术后3天也下降了46%（P<0.02），在7天下降了78%（P<0.01）。DNA聚合酶β的mRNA量与酶活性平行下降。由于睾丸DNA聚合酶β对热失活的敏感性与肝脏中的完全相同，DNA聚合酶β活性的下降可能至少部分是由于酶蛋白生物合成减少。隐睾睾丸的形态学变化表明，DNA聚合酶β和γ活性的下降可能与温度升高对精子发生的有害影响有关。
