Chiocchio S R, Negro-Vilar A, Tramezzani J H
Endocrinology. 1976 Aug;99(2):629-34. doi: 10.1210/endo-99-2-629.
Median eminence catecholamines were measured in individual samples from intact, castrated, or sham-operated male rats, in order to correlate changes in catecholamine content with the early post-castration rise in serum LH levels. Both norepinephrine (NE) and dopamine (DA) were measured by an enzymatic-isotopic assay and advantage was also taken of a method recently developed that makes it possible to obtain the median eminence free of the surrounding hypothalamus. Determinations were made at 4, 8, or 24 h after surgery. All animals were killed between 1400 and 1600 h. It was observed that castration increases the ME content of NE significantly at all the times studied, with peak values 8 h after orchidectomy. Sham operation induced a significant decrease in NE content in the ME 4 h after surgery. By 8 h the NE values had returned to intact control levels. Both castration and sham operation induced a significant decrease in DA levels 4 h after surgery. By 8 h, DA values had returned to intact control levels in both groups. When the NE levels in castrated rats had reached the highest value, serum LH values had not departed from control levels, indicating that the change in NE content in the ME takes place prior to the expected rise in LH. Testosterone replacement therapy (40 mug/100 gBW) of castrated rats blocked the increase in NE content observed 8 h after castration. Dopamine levels were not affected by this treatment. These results support the concept that the NE contained in median eminence catecholaminergic terminals participates in the feed-back regulation of LH secretion in the male rat, while DA is apparently not involved under the present conditions.
为了将儿茶酚胺含量的变化与去势后血清促黄体生成素（LH）水平的早期升高联系起来，对完整、去势或假手术的雄性大鼠的各个样本中的正中隆起儿茶酚胺进行了测量。通过酶促同位素分析法测量去甲肾上腺素（NE）和多巴胺（DA），并且还利用了最近开发的一种方法，该方法能够获取不含周围下丘脑的正中隆起。在手术后4、8或24小时进行测定。所有动物均在1400至1600时之间处死。观察到，在所有研究的时间点，去势均显著增加NE的正中隆起含量，在睾丸切除术后8小时达到峰值。假手术在术后4小时导致正中隆起中NE含量显著降低。到8小时时，NE值已恢复到完整对照组水平。去势和假手术在术后4小时均导致DA水平显著降低。到8小时时，两组的DA值均已恢复到完整对照组水平。当去势大鼠的NE水平达到最高值时，血清LH值尚未偏离对照水平，这表明正中隆起中NE含量的变化发生在LH预期升高之前。对去势大鼠进行睾酮替代疗法（40μg/100g体重）可阻断去势后8小时观察到的NE含量增加。多巴胺水平不受该治疗的影响。这些结果支持以下概念，即正中隆起儿茶酚胺能终末中所含的NE参与雄性大鼠LH分泌的反馈调节，而在当前条件下DA显然不参与。
