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。最初，我们将 分析脑垂体内聚合和解聚的微管蛋白水平 A)在不同生理条件下哺乳，以及b) 在给予多巴胺激动剂或拮抗剂后，TRH、VIP和 OT，已知会改变PRL的转变程度，以及 释放了。接下来我们将调查微管的解体是否 在垂体前叶由药物(秋水仙碱、长春花碱)伴发 哺乳后催乳素转化和释放的变化 在体内，或在体外孵育垂体前叶后。我们 将使用~3H-秋水仙碱结合，鸟苷三磷酸(GTP)水解， 微管蛋白放射免疫分析评估垂体前叶的数量变化 在这些研究中，微管蛋白和EM证实微管蛋白的解体已经 发生了。我们还将使用免疫电子显微镜来研究 脑垂体前叶微管的形态改变 对哺乳的反应，我们将把这些与生理和 催乳素分泌的生化指标。我们将检验这一假设 CAMP介导哺乳对微管蛋白的调节作用 聚合-解聚与PRL转化和 放手。哺乳后脑垂体cAMP的变化 多潘立酮将被监测。此外，二丁酰cAMP的影响， 体内注射或体内添加的磷酸二酯酶抑制剂和Forsklin 体外，对脑垂体微管蛋白进行评估。我们将使用体外培养的 将微管蛋白组装成微管以评估哺乳和 在体内和体外添加多巴胺、TRH、VIP和OT的速率 微管形成。这样形成的微管将与 以PRL颗粒为研究对象，通过EM和解聚 技术，催乳素和微管之间的联系的性质。我们 将把这一准备工作作为一个模型来开发，既要建立 结合中可能需要的或影响结合的细胞内因素 PRL颗粒对微管的影响，并评价影响因素 影响催乳素与微管的解偶联。

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.