Pisera D, Theas S, De Laurentiis A, Lasaga M, Duvilanski B, Seilicovich A
Centro de Investigaciones en Reproducción, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
J Endocrinol. 1998 Dec;159(3):389-95. doi: 10.1677/joe.0.1590389.
We have previously reported that neurokinin A (NKA), a tachykinin closely related to substance P, increases the release of prolactin (PRL) from the anterior pituitary gland of male rats, but not from pituitaries of ovariectomized (OVX) female rats. In this study, we evaluated the influence of estrogens in the action of NKA on PRL secretion in female rats. NKA stimulated the in vitro release of PRL from pituitary glands of OVX-chronically estrogenized rats, and of proestrus and estrus rats, but had no effect in anterior pituitaries of diestrus rats. In addition, we observed that cultured anterior pituitary cells of OVX rats responded to NKA only when they were incubated for 3 days in the presence of estradiol 10(-9) M. This effect was blocked by L-659,877, an NK-2 receptor antagonist. We also studied the action of NKA on PRL release during lactation. The response of anterior pituitary cells to NKA was variable over this period. The maximal sensitivity to NKA was observed at day 10 of lactation. Furthermore, the blockade of endogenous NKA by the administration of an anti-NKA serum to lactating rats reduced the PRL surge induced by the suckling stimulus. These results show that the responsiveness of the anterior pituitary gland of female rats to NKA is modulated by the endocrine environment, and suggest that NKA may participate in the control of PRL secretion during the estrus cycle and lactation.
我们之前曾报道，神经激肽A（NKA），一种与P物质密切相关的速激肽，可增加雄性大鼠垂体前叶催乳素（PRL）的释放，但对去卵巢（OVX）雌性大鼠的垂体则无此作用。在本研究中，我们评估了雌激素在NKA对雌性大鼠PRL分泌作用中的影响。NKA刺激了长期雌激素化的OVX大鼠、动情前期和动情期大鼠垂体前叶PRL的体外释放，但对动情间期大鼠的垂体前叶无影响。此外，我们观察到，OVX大鼠培养的垂体前叶细胞仅在10^(-9)M雌二醇存在下孵育3天时才对NKA有反应。这种作用被NK-2受体拮抗剂L-659,877阻断。我们还研究了NKA在哺乳期对PRL释放的作用。在此期间，垂体前叶细胞对NKA的反应是可变的。在哺乳期第10天观察到对NKA的最大敏感性。此外，给哺乳期大鼠注射抗NKA血清阻断内源性NKA可减少哺乳刺激诱导的PRL激增。这些结果表明，雌性大鼠垂体前叶对NKA的反应性受内分泌环境调节，并提示NKA可能参与发情周期和哺乳期PRL分泌的调控。
