Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan.
Anim Sci J. 2013 Apr;84(4):334-40. doi: 10.1111/asj.12002. Epub 2012 Nov 19.
The aim of the present study was to clarify the effect of melatonin (MEL) on the salsolinol (SAL)-induced release of prolactin (PRL) in goats. Female goats were kept at 20°C with 16 h of light, 8 h of darkness, and orally administered saline or MEL for 5 weeks. A single intravenous (i.v.) injection of saline (controls), SAL, thyrotropin-releasing hormone (TRH) or a dopamine receptor antagonist, sulpiride, was given to the goats 3 weeks after the first oral administrations of saline or MEL, and the responses were compared. The mean basal plasma PRL concentrations in the control group were higher for the saline treatments than MEL treatments (P < 0.05). SAL as well as TRH and sulpiride stimulated the release of PRL promptly after each injection in both the saline- and MEL-treated groups (P < 0.05). The area under the response curve of PRL for the 60-min period after the i.v. injection of SAL, TRH and sulpiride in the saline-treated group was greater than each corresponding value in the MEL-treated group (P < 0.05). These results show that daily exposure to MEL under a long day length reduces the PRL-releasing response to SAL as well as TRH and sulpiride in goats.
本研究旨在阐明褪黑素（MEL）对山羊体内索洛辛醇（SAL）诱导的催乳素（PRL）释放的影响。雌性山羊在 20°C 的环境中生活，光照 16 小时，黑暗 8 小时，口服生理盐水或 MEL 连续 5 周。在首次口服生理盐水或 MEL 后的第 3 周，向山羊单次静脉内（i.v.）注射生理盐水（对照组）、SAL、促甲状腺素释放激素（TRH）或多巴胺受体拮抗剂舒必利，并比较其反应。在对照组中，生理盐水处理组的基础血浆 PRL 浓度平均值高于 MEL 处理组（P<0.05）。SAL 以及 TRH 和舒必利在生理盐水和 MEL 处理组中均能迅速刺激 PRL 的释放（P<0.05）。在 i.v.注射 SAL、TRH 和舒必利后的 60 分钟内，生理盐水处理组的 PRL 反应曲线下面积大于 MEL 处理组的相应值（P<0.05）。这些结果表明，在长光照条件下，每日暴露于 MEL 会降低山羊对 SAL 以及 TRH 和舒必利的 PRL 释放反应。
