NEURAL AND HORMONAL REGULATION OF LACTATION

拟议调查的目的是阐明 微管参与PRL转化的细胞内机制 并在哺乳期大鼠哺乳后释放。 首先，我们将 分析垂体内聚合和解聚微管蛋白水平 a）在不同生理条件下的哺乳期间，和B） 在施用多巴胺激动剂或拮抗剂、TRH、VIP和 OT，已知其改变PRL转化的程度， 发布 接下来我们将研究微管的解体是否 在垂体前叶所用药物（秋水仙碱、长春碱）的陪同下 通过哺乳后PRL的转化和释放的改变 体内或在体外培养垂体前叶后。 我们 将使用3H-秋水仙碱结合，鸟苷三磷酸（GTP）水解， 和微管蛋白RIA来评估垂体前叶的定量变化 微管蛋白在这些研究中，和EM，以确认微管蛋白解体， 发生了。 我们还将使用免疫电子显微镜来研究 垂体前叶微管的形态学改变发生在 对吮吸的反应，我们将把这些与生理和 PRL分泌的生化指标。 我们将检验这个假设， cAMP介导哺乳对微管蛋白的调节作用 与PRL转化相关的聚合-解聚， release. 哺乳或哺乳后垂体cAMP的变化 将监测多潘立酮。 此外，双丁酰cAMP， 磷酸二酯酶抑制剂和毛喉素，体内注射或加入 体外，将评估垂体微管蛋白。 我们将使用体外 微管蛋白组装成微管以评估哺乳的影响， 多巴胺，TRH，VIP和OT在体内和体外加入的速度， 微管形成。 这样形成的微管将与 以PRL颗粒为考察对象，通过电镜观察和解聚 技术，PRL和微管之间的关联的性质。 我们 将开发这种准备作为一种模式，既要建立 可能需要或影响结合的细胞内因子 PRL颗粒的微管，并评估这些因素， 影响PRL与微管的解偶联。

The purpose of the proposed investigation is to elucidate the role of microtubules in the intracellular mechanisms involved in PRL transformation and release in the lactating rat following suckling. Initially, we will analyze polymerized and depolymerized tubulin levels within the pituitary a) during suckling under different physiological conditions, and b) following administration of dopamine agonists or antagonists, TRH, VIP, and OT, which are known to alter the extent to which PRL is transformed and released. Next we will investigate whether the disassembly of microtubules in the anterior pituitary by drugs (colchicine, vinblastine) is accompanied by alterations in the transformation and release of PRL following suckling in vivo, or following incubation of the anterior pituitary in vitro. We will use 3H-colchicine binding, guanosine triphosphate (GTP) hydrolysis, and tubulin RIA to assess quantitative changes in anterior pituitary tubulin in these studies, and EM to confirm that tubulin disassembly has occurred. We will also use immuno-electron microscopy to investigate morphologic alterations in anterior pituitary microtubules that occur in response to suckling, and we will correlate these with physiological and biochemical indices of PRL secretion. We will test the hypothesis that cAMP mediates the effect of suckling in the regulation of tubulin polymerization-depolymerization in association with PRL transformation and release. Changes in cAMP in the pituitary following suckling or domperidone will be monitored. Also, the effects of dibutyryl cAMP, phosphodiesterase inhibitors, and forskolin, injected in vivo or added in vitro, upon pituitary tubulin will be assessed. We will use the in vitro assembly of tubulin into microtubules to assess the effect of suckling and of dopamine, TRH, VIP, and OT added in vivo and in vitro upon the rate of microtubule formation. The microtubules thus formed will be incubated with PRL granules in order to investigate, by EM and depolymerization techniques, the nature of the association between PRL and microtubules. We will develop this preparation as a model, both to establish the intracellular factors that may be required in or that influence the binding of PRL granules to microtubules, and to evaluate those factors which influence the uncoupling of PRL from microtubules.