Becú-Villalobos D, Thyssen S M, Rey E B, Lux-Lantos V, Libertun C
Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina.
Proc Soc Exp Biol Med. 1992 Feb;199(2):230-5. doi: 10.3181/00379727-199-43352.
Trace amines are a group of biogenic amines that are present in neural tissue in concentrations ranging from 0.1 to 100 ng/g. In the present work, we examined the action of two trace amines, octopamine and phenylethylamine, which are found in the hypothalamus, on pituitary hormone secretion in different experimental situations in vivo and in dispersed anterior pituitary cells. Both octopamine and phenylethylamine decreased high prolactin levels due to swimming or immobilization stress without affecting other adenohypophysial hormones. With regard to the hypoprolactinemic potencies in the immobilization stress model, it was observed that p-tyramine, another trace amine, was as potent as octopamine. Phenylethylamine was the least effective. To evaluate the site of action of the effect described, the three trace amines were tested in dispersed anterior pituitary cell cultures in vitro. Tyramine and octopamine reduced prolactin secretion in a concentration-dependent manner, at concentrations of 10(-8) to 10(-5) M, whereas the hypoprolactinemic effect observed for phenylethylamine was very weak. In pharmacologic experiments, neither octopamine nor phenylethylamine reduced prolactin release when dopaminergic receptors were blocked. This could mean that their hypoprolactinemic action was mediated through the release of dopamine, or it could be a direct action at a dopaminergic receptor. This is the first description of a specific endocrine action both in vivo and in vitro for octopamine and phenylethylamine. Further studies are needed to ascertain the physiologic or pathologic implication of these findings.
痕量胺是一类生物胺，存在于神经组织中，浓度范围为0.1至100 ng/g。在本研究中，我们检测了下丘脑中发现的两种痕量胺——章鱼胺和苯乙胺，在体内不同实验情况下以及分散的垂体前叶细胞中对垂体激素分泌的作用。章鱼胺和苯乙胺均可降低因游泳或固定应激导致的高催乳素水平，而不影响其他腺垂体激素。在固定应激模型中，就降低催乳素水平的效力而言，观察到另一种痕量胺对羟基苯乙胺与章鱼胺效力相当。苯乙胺效果最差。为评估所述效应的作用位点，在体外分散的垂体前叶细胞培养物中对这三种痕量胺进行了测试。对羟基苯乙胺和章鱼胺在10(-8)至10(-5) M浓度范围内以浓度依赖方式降低催乳素分泌，而苯乙胺的降催乳素作用非常微弱。在药理学实验中，当多巴胺能受体被阻断时，章鱼胺和苯乙胺均未降低催乳素释放。这可能意味着它们的降催乳素作用是通过多巴胺释放介导的，或者可能是对多巴胺能受体的直接作用。这是首次在体内和体外对章鱼胺和苯乙胺的特异性内分泌作用进行描述。需要进一步研究以确定这些发现的生理或病理意义。
