McCann S M, Vijayan E, Negro-Vilar A, Mizunuma H, Mangat H
Psychoneuroendocrinology. 1984;9(2):97-106. doi: 10.1016/0306-4530(84)90029-5.
We have evaluated the role of GABA in the control of anterior pituitary (AP) hormone secretion by injecting it into the third ventricle of ovariectomized, ovariectomized-steroid primed and male rats. Specificity of the effects was determined by injecting the GABA blocker, bicuculline. The action of GABA directly on the pituitary was evaluated in vitro. The results indicate that intraventricular GABA can stimulate LH, growth hormone (GH) and, at high doses, prolactin (Prl) release, whereas low doses inhibit Prl and al doses inhibit TSH release. All of these actions are blocked by bicuculline. Intraventricular GABA administration is followed by an elevation of hypothalamic norepinephrine (NE) and median eminence dopamine (DA) levels and AP DA levels, which indicates that the compound stimulates both NE and DA release. The actions on GH and LH appear to proceed independently of DA, since the DA receptor blocker, pimozide, did not interfere with these effects, whereas the action to elevate Prl and to lower TSH was blocked by DA receptor blockade. Anterior pituitary hormone release by AP's incubated with GABA in vitro was unaltered except for an inhibition of Prl release by very high GABA doses, which could be blocked by bicuculline. Intravenous injection of bicuculline to assess the physiological significance of GABA in control of AP hormone secretion revealed no effect on FSH but a delayed rise in LH, an initial rise in Prl, followed by a fall, a tendency for GH values to rise and dramatic fall in TSH levels. These results suggest the possibility that GABA plays a physiological role in the control of AP hormone secretion, mainly via a hypothalamic action.
我们通过将γ-氨基丁酸（GABA）注入去卵巢大鼠、去卵巢并用类固醇预处理的大鼠以及雄性大鼠的第三脑室，评估了GABA在控制垂体前叶（AP）激素分泌中的作用。通过注射GABA拮抗剂荷包牡丹碱来确定效应的特异性。在体外评估了GABA对垂体的直接作用。结果表明，脑室内注射GABA可刺激促黄体生成素（LH）、生长激素（GH）释放，高剂量时还可刺激催乳素（Prl）释放，而低剂量则抑制Prl释放，所有剂量均抑制促甲状腺激素（TSH）释放。所有这些作用均被荷包牡丹碱阻断。脑室内注射GABA后，下丘脑去甲肾上腺素（NE）、正中隆起多巴胺（DA）水平以及垂体前叶DA水平升高，这表明该化合物可刺激NE和DA释放。对GH和LH的作用似乎独立于DA进行，因为DA受体阻滞剂匹莫齐特并不干扰这些效应，而升高Prl和降低TSH的作用则被DA受体阻断所抑制。除了极高剂量的GABA抑制Prl释放（可被荷包牡丹碱阻断）外，体外与GABA一起孵育的垂体前叶激素释放未发生改变。静脉注射荷包牡丹碱以评估GABA在控制垂体前叶激素分泌中的生理意义，结果显示对促卵泡激素（FSH）无影响，但LH延迟升高，Prl先升高后下降，GH值有升高趋势，TSH水平急剧下降。这些结果提示，GABA可能主要通过下丘脑作用在控制垂体前叶激素分泌中发挥生理作用。
