Roselli C E, Cross E, Poonyagariyagorn H K, Stadelman H L
Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97210, USA.
Horm Behav. 2003 Aug;44(2):146-51. doi: 10.1016/s0018-506x(03)00123-5.
The present study was designed to test the hypothesis that aromatization is involved in the maintenance by testosterone of the appetitive component of male sexual behavior. We measured appetitive sexual behavior by administering behavioral tests in bilevel chambers and quantifying anticipatory level changes during a 5-min period prior to introduction of a stimulus female. In addition, we recorded standard measures of consummatory male sexual behavior after the female was introduced. Following 3 weekly tests, level-changing behavior reached a plateau and remained stable for up to 10 weeks. After 10 bilevel tests, rats were given subcutaneous testosterone capsules to clamp circulating androgen at physiological levels. Rats were tested and divided into two groups that were matched for measures of sexual behavior. One group was then treated with the nonsteroidal aromatase inhibitor, Fadrozole (2.5 mg/kg/day), given subcutaneously in beta-cyclodextrin and the other group was treated with vehicle. Within 1 week of Fadrozole treatment, the number of anticipatory levels changes was significantly reduced, but not the latency to begin searching. Fadrozole treatment also significantly reduced all measures of copulatory behavior over the period of treatment and increased latencies to first mount, intromission, and ejaculation. After 8 weeks, both treatment groups were given an additional Silastic capsule filled with estradiol and tested for 4 additional weeks. Estrogen treatment partially restored level-changing behavior, mounts, and intromissions but had little effect on ejaculations. These results support the view that aromatization is important for maintaining both the appetitive and the consummatory aspects of sexual behavior in male rats.
本研究旨在验证一个假设，即芳香化作用参与睾酮对雄性性行为中欲求成分的维持过程。我们通过在双层实验箱中进行行为测试，并对引入刺激雌性前5分钟内的预期水平变化进行量化，来测量欲求性行为。此外，在引入雌性后，我们记录了雄性性行为的标准完成指标。经过3周的每周测试，水平变化行为达到平稳状态，并在长达10周的时间内保持稳定。在进行10次双层实验后，给大鼠皮下植入睾酮胶囊，以使循环雄激素维持在生理水平。对大鼠进行测试并将其分为两组，两组在性行为指标上相互匹配。然后，一组用非甾体芳香化酶抑制剂法倔唑（2.5毫克/千克/天）进行治疗，该抑制剂以β-环糊精为载体皮下注射，另一组用赋形剂治疗。在法倔唑治疗的1周内，预期水平变化的次数显著减少，但开始搜寻的潜伏期没有变化。法倔唑治疗在治疗期间还显著降低了所有交配行为指标，并延长了首次爬上、插入和射精的潜伏期。8周后，给两个治疗组都额外植入了一个装有雌二醇的硅橡胶胶囊，并再进行4周的测试。雌激素治疗部分恢复了水平变化行为、爬上和插入行为，但对射精影响不大。这些结果支持了这样一种观点，即芳香化作用对于维持雄性大鼠性行为的欲求方面和完成方面都很重要。
