Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autonoma de Mexico, Queretaro, Mexico.
Biol Reprod. 2011 Jan;84(1):118-23. doi: 10.1095/biolreprod.110.086116. Epub 2010 Sep 1.
Thyronines are essential for the development of the male reproductive system, including the prostate gland. Metabolically active 3,5,3' triiodothyronine (T(3)) is generated mainly by the extrathyroidal, enzymatic 5'deiodination of the prohormone thyroxine (T(4)), which is catalyzed by deiodinases type 1 (D1) and type 2 (D2). Prostate D1 activity is highly expressed during puberty and declines with age, but continuous, long-term sexual activity prevents this reduction. The aims of this study were to characterize the changes in prostatic D1 activity in response to consecutive ejaculations and to determine whether sympathetic input participates in the local T(3) generation (D1 activity). D1 activity was analyzed in prostates of sexually experienced, 4-mo-old male rats after one to five ejaculations. D1 activity, T(3) concentrations, and the T(3)-dependent gene ornithine decarboxylase (Odc) were measured after the fourth ejaculation in prostates of intact, sham, and sympathectomized (Smpx, hypogastric nerve) rats. D1 activity was evaluated by the radio-iodine-release method; T(3) was measured by radioimmunoassay and Odc expression by real-time PCR. Data showed a gradual increase of prostate D1 activity in response to consecutive ejaculations. The highest activity was found after the fourth ejaculation, and it decreased after the fifth. The increase of prostate D1 activity after ejaculation was blocked in Smpx males as compared to intact or sham animals. The changes in D1 activity correlate with prostatic T(3) concentrations and Odc expression. Circulating levels of T(3) were not affected by consecutive ejaculations or by Smpx. These findings indicate that the postejaculatory increase in prostatic generation of T(3) depends on sympathetic input.
甲状腺素对于男性生殖系统的发育至关重要，包括前列腺。代谢活跃的 3,5,3'三碘甲状腺原氨酸（T(3)）主要由甲状腺素（T(4)）的甲状腺外酶 5'脱碘生成，该过程由脱碘酶 1 型（D1）和 2 型（D2）催化。前列腺 D1 活性在青春期表达量高，随年龄增长而下降，但持续的长期性行为可防止这种下降。本研究旨在描述前列腺 D1 活性对连续射精的反应变化，并确定交感神经输入是否参与局部 T(3)生成（D1 活性）。研究分析了 4 月龄有性经验雄性大鼠在 1 至 5 次射精后的前列腺 D1 活性。在完整、假手术和交感神经切除（Smpx，腹下神经）大鼠的前列腺中，在第四次射精后测量了 D1 活性、T(3)浓度和 T(3)依赖性基因鸟氨酸脱羧酶（Odc）。D1 活性通过放射性碘释放法评估；T(3)通过放射免疫测定法测量，Odc 表达通过实时 PCR 测量。数据显示，前列腺 D1 活性随着连续射精逐渐增加。第四次射精后活性最高，第五次射精后活性降低。与完整或假手术动物相比，Smpx 雄性的射精后前列腺 D1 活性增加被阻断。D1 活性的变化与前列腺 T(3)浓度和 Odc 表达相关。连续射精或 Smpx 不影响循环 T(3)水平。这些发现表明，射精后前列腺 T(3)生成的增加依赖于交感神经输入。
