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 并在哺乳后的哺乳大鼠中释放。 最初，我们将 分析垂体内聚合和解聚的微管蛋白水平 a) 不同生理条件下的哺乳期间，b) 服用多巴胺激动剂或拮抗剂、TRH、VIP 和 OT，已知会改变 PRL 转化的程度， 释放。 接下来我们将研究微管的拆卸是否 在垂体前叶由药物（秋水仙碱，长春花碱）伴随 通过哺乳后 PRL 转化和释放的改变 体内，或在体外培养垂体前叶后。 我们 将利用 3H-秋水仙碱结合、三磷酸鸟苷 (GTP) 水解， 和微管蛋白 RIA 评估垂体前叶的数量变化 这些研究中的微管蛋白，以及 EM 来确认微管蛋白分解已 发生。 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 对哺乳的反应，我们会将这些与生理和 PRL分泌的生化指标。 我们将检验以下假设： cAMP介导哺乳对微管蛋白调节的作用 与 PRL 转化相关的聚合-解聚和 释放。 哺乳后垂体中 cAMP 的变化 将监测多潘立酮。 此外，二丁酰 cAMP 的作用， 磷酸二酯酶抑制剂和毛喉素，体内注射或添加 体外，将评估垂体微管蛋白。 我们将使用体外 将微管蛋白组装成微管以评估哺乳和 体内和体外添加的多巴胺、TRH、VIP 和 OT 的比率 微管形成。 由此形成的微管将与 PRL 颗粒以便通过 EM 和解聚进行研究 技术，PRL 和微管之间关联的性质。 我们 将开发这种制剂作为模型，既要建立 可能需要或影响结合的细胞内因子 PRL 颗粒与微管的关系，并评估影响这些因素的因素 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.