Arias P, Jarry H, Convertini V, Ginzburg M, Wuttke W, Moguilevsky J
Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
Amino Acids. 1998;15(1-2):5-11. doi: 10.1007/BF01345276.
Taurine (Tau), a putative inhibitory amino acid neurotransmitter, has been shown to stimulate prolactin (PRL) release. Using ovariectomized, estrogen-replaced adult rats we investigated initially the effect of this amino acid, injected by different routes, on PRL secretion in vivo. Tau (100-500 mg/kg) had no effect on PRL release when given i.p.; 15 min after i.c.v. injection of Tau (3 mumoles), a significant increase in serum PRL levels was observed (78 +/- 9 ng/ml over basal levels, p < 0.01 vs. controls). In vitro (cultured anterior pituitary cells) PRL release was not affected by a 5 h incubation with Tau (10(-3)-10(-8) M). Basal dopamine (DA) or gamma-aminobutyric acid (GABA) output from superfused mediobasal hypothalamic fragments (MBH) was not affected by Tau (10(-3) M or 10(-5) M). However, during stimulation with KCl (50 mM), Tau (10(-3) M) significantly lowered DA release, and increased GABA output. It is concluded that Tau acts at a central level to increase PRL secretion, most probably by modulating the hypothalamic release of neurotransmitters controlling lactotroph function.
牛磺酸（Tau）是一种假定的抑制性氨基酸神经递质，已被证明能刺激催乳素（PRL）释放。我们使用去卵巢、雌激素替代的成年大鼠，首先研究了通过不同途径注射这种氨基酸对体内PRL分泌的影响。腹腔注射牛磺酸（100 - 500 mg/kg）对PRL释放没有影响；脑室内注射牛磺酸（3微摩尔）15分钟后，观察到血清PRL水平显著升高（比基础水平高78±9 ng/ml，与对照组相比p < 0.01）。在体外（培养的垂体前叶细胞），与牛磺酸（10⁻³ - 10⁻⁸ M）孵育5小时对PRL释放没有影响。来自灌流的下丘脑中间基底部片段（MBH）的基础多巴胺（DA）或γ-氨基丁酸（GABA）输出不受牛磺酸（10⁻³ M或10⁻⁵ M）影响。然而，在氯化钾（50 mM）刺激期间，牛磺酸（10⁻³ M）显著降低DA释放，并增加GABA输出。得出的结论是，牛磺酸在中枢水平发挥作用以增加PRL分泌，很可能是通过调节控制催乳素细胞功能的神经递质的下丘脑释放来实现的。
