Kyprianou N, Isaacs J T
Prostate. 1987;10(4):313-24. doi: 10.1002/pros.2990100405.
Within 12 hr after castration, there is a dramatic drop in the serum testosterone (T) levels to approximately 1.3% of the intact value (2.5 +/- 0.8 ng/ml). By 1 day following castration, the serum T levels are approximately 3.3% of the intact control level. In contrast, serum 5 alpha-dihydrotestosterone (DHT) levels decrease to only 50% of the intact value within 12 hr postcastration and remain at a value greater than 50% of the intact control level even following long-term castration for up to 20 weeks. Following castration, tissue T and DHT concentrations in rat ventral prostate (RVP) exhibited a similar sequence of changes. Within 12 hr after castration, there is a substantial decrease in T to 27% and DHT to 20% of their intact values; after a further transient decrease during the subsequent 7 days, these levels remain constant with RVP at approximately 40% for T and 20% for DHT of the intact control levels even following long-term castration. Thus castration induces only a partial withdrawal of the tissue androgens. The low but measurable androgen levels in RVP of castrated host are of adrenal origin, since following surgical adrenalectomy these remaining androgen levels become undetectable. Thus castration plus adrenalectomy produces a complete androgen withdrawal within the RVP. To determine the biological significance of the measurable androgen levels remaining following castration, the RVP cell number and the rate of prostatic DNA synthesis were compared in RVP following castration alone (ie, partial androgen withdrawal) or castration combined with surgical adrenalectomy (ie, complete androgen withdrawal). These results demonstrated that complete elimination of the remaining androgens in the RVP of long-term castrates, by means of surgical adrenalectomy, did not induce any further reduction in either of these prostatic growth parameters. Therefore, in the rat, DHT must be decreased to a critical threshold but does not have to be completely eliminated to decrease maximally androgen effect on the prostate.
去势后12小时内，血清睾酮（T）水平急剧下降至完整值的约1.3%（2.5±0.8 ng/ml）。去势后1天，血清T水平约为完整对照水平的3.3%。相比之下，血清5α-双氢睾酮（DHT）水平在去势后12小时内仅降至完整值的50%，即使在长达20周的长期去势后，仍保持在大于完整对照水平50%的值。去势后，大鼠腹侧前列腺（RVP）中的组织T和DHT浓度呈现出相似的变化顺序。去势后12小时内，T降至其完整值的27%，DHT降至20%；在随后的7天内进一步短暂下降后，即使经过长期去势，这些水平仍保持恒定，RVP中T约为完整对照水平的40%，DHT约为20%。因此，去势仅诱导组织雄激素的部分撤离。去势宿主RVP中低但可测量的雄激素水平来自肾上腺，因为手术切除肾上腺后，这些剩余的雄激素水平变得无法检测到。因此，去势加肾上腺切除术可使RVP内的雄激素完全撤离。为了确定去势后剩余可测量雄激素水平的生物学意义，比较了单独去势（即部分雄激素撤离）或去势联合手术切除肾上腺（即完全雄激素撤离）后RVP中的RVP细胞数量和前列腺DNA合成速率。这些结果表明，通过手术切除肾上腺完全消除长期去势大鼠RVP中剩余的雄激素，并未导致这些前列腺生长参数中的任何一个进一步降低。因此，在大鼠中，DHT必须降至临界阈值，但不必完全消除即可最大程度降低雄激素对前列腺的作用。
