Justo S N, Rossano G L, Szwarcfarb B, Rubio M C, Moguilevsky J A
Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
Neuroendocrinology. 1989 Oct;50(4):382-6. doi: 10.1159/000125252.
The present experiments were designed to assess the effect of the serotoninergic system on FSH secretion in prepubertal (16-, 18-, 20-, 26- and 30-day-old) and adult (60-day-old) male and female rats. The intraperitoneal administration of 5-hydroxytryptophan (5-HTP), a serotonin (5-HT) precursor, induced a significant increase of FSH levels in male rats at 16, 26, 30 and 60 days of age (p less than 0.01) but not at 18 and 20 days. In the females, no modifications in FSH concentrations in prepubertal and adult rats were observed after 5-HTP injection. These results indicate that there are sexual differences in the effect of the serotoninergic system on FSH secretion. Orchidectomy performed in prepubertal (30-day-old) and adult rats (60 days) besides increasing FSH levels, reversed the response of this hormone to 5-HTP administration, since in castrated rats the 5-HT precursor induced a significant decrease in serum FSH concentrations. The administration of 5-HTP to 30 day-old castrated rats treated with testosterone induced FSH release as it did in control animals of this age. In the adult castrated rats the administration of testosterone abolished the inhibitory effect of 5-HTP observed in castrated rats but did not invoke the stimulatory action of 5-HTP observed in the controls. This difference between prepubertal and adult rats appears to be related to a decrease in the sensitivity to testosterone of the central mechanism which controls FSH secretion. These results indicate that 5-HTP stimulates FSH release in normal rats and inhibits FSH release in castrated rats, testosterone concentration being a relevant factor in determining the 'type' of effect produced. The hypothalamic concentrations of 5-HT and 5-hydroxy-indoleacetic acid (5-HIAA) are significantly higher at the ages at which 5-HTP induces FSH release than at other ages suggesting that hypothalamic turnover of these substances is related is related to the releasing effect of 5-HTP on FSH.
本实验旨在评估血清素能系统对青春期前（16、18、20、26和30日龄）及成年（60日龄）雄性和雌性大鼠促卵泡激素（FSH）分泌的影响。腹腔注射血清素（5-HT）前体5-羟色氨酸（5-HTP），可使16、26、30和60日龄雄性大鼠的FSH水平显著升高（p<0.01），但对18和20日龄大鼠无此作用。对雌性大鼠注射5-HTP后，青春期前和成年大鼠的FSH浓度均未发生改变。这些结果表明，血清素能系统对FSH分泌的影响存在性别差异。对青春期前（30日龄）和成年（60日龄）大鼠进行去势手术，除了会使FSH水平升高外，还会逆转该激素对5-HTP给药的反应，因为在去势大鼠中，5-HT前体会使血清FSH浓度显著降低。对30日龄经睾酮处理的去势大鼠注射5-HTP可诱导FSH释放，这与该年龄的对照动物情况相同。在成年去势大鼠中，注射睾酮可消除在去势大鼠中观察到的5-HTP抑制作用，但不会引发在对照动物中观察到的5-HTP刺激作用。青春期前和成年大鼠之间的这种差异似乎与控制FSH分泌的中枢机制对睾酮敏感性的降低有关。这些结果表明，5-HTP可刺激正常大鼠释放FSH，并抑制去势大鼠释放FSH，睾酮浓度是决定所产生“效应类型”的一个相关因素。5-HTP诱导FSH释放的年龄阶段，下丘脑5-HT和5-羟吲哚乙酸（5-HIAA）的浓度显著高于其他年龄阶段，这表明这些物质的下丘脑周转率与5-HTP对FSH的释放作用有关。
