SECOND MESSENGER FUNCTION IN EXOCRINE GLANDS

唾液腺和胰腺的分泌机制需要 Ca 2+和环核苷酸，但这些第二个确切的作用， 信使及其胞质浓度的调节仅 部分理解。 这些研究将评估假设， 第二信使浓度的控制部分地受到第二信使的影响， 使者自己。 这一假设将在比较中得到检验。 使用大鼠下颌下腺的腺泡制备物的研究， 胰腺作为模型系统，以（1）表征动力学和调节 控制第二信使浓度的酶的性质： 高亲和力CaATP酶和活性Ca 2+转运、腺苷酸和 鸟苷酸环化酶活性和cAMP和cGMP磷酸二酯酶 活动;和（2）表征的形式的动力学特性， 这些酶受Ca 2 +-钙调素复合物的调节。 第二个目标是 这些研究是为了确定第二信使对激酶的影响， 活动的外分泌腺和评估的假设，分泌 依赖于第二信使调节的蛋白磷酸化。 聚丙烯酰胺凝胶电泳和放射自显影将用于 检测和表征受调节激酶的磷酸化底物 被第二信使破坏 在其他研究中， 将功能性腺泡制备物与P32孵育以标记 然后将细胞内ATP暴露于胆碱能、α和β肾上腺素能或 肽能剂。 分泌反应（K+释放， 淀粉酶或从分泌的糖蛋白释放的唾液酸）将被 在此后的不同时间测量，并与蛋白质的变化相关联， 磷酸化 在平行研究中，腺泡将暴露于 在存在抑制、增强和/或模拟 第二信使的影响，以关联的变化， 第二信使依赖性磷酸化与分泌的变化 反应 这些研究将提供有关 明确模型外分泌的刺激-分泌偶联机制 系统，并将提供有关比较生理学的新见解 与多种疾病有关的分泌系统。 另外这些 研究将是重要的，在确定因素，调节正常的， 唾液腺功能，因此对于维持 口腔中的健康软组织和矿化组织。

The mechanism of secretion in salivary glands and the pancreas requires Ca2+ and the cyclic nucleotides, but the precise roles of those second messengers and the regulation of their cytosolic concentrations are only partially understood. These studies will evaluate the hypothesis that control of second messenger concentration effected, in part, by the second messengers themselves. This hypothesis will be tested in comparative studies using acinar preparations of the rat submandibular gland and pancreas as model systems to (1) characterize the kinetic and regulatory properties of the enzymes that control second messenger concentration: high affinity CaATPase and active Ca2+ translocation, adenylate and guanylate cyclase activities and cAMP and cGMP phosphodiesterase activities; and (2) characterize the kinetic properties of the forms of those enzymes regulated by the Ca2+-calmodulin complex. A second goal of these studies is to determine the effects of second messengers on kinase activities in exocrine glands and to evaluate the hypothesis that secretion depends on second messenger-regulated protein phosphorylation. Polyacrylamide gel electrophoresis and autoradiography will be used to detect and characterize the phosphorylated substrates of kinases regulated by the second messengers in broken acinar cells. In other studies, functioning acinar preparations will be incubated with P32 to label intracellular ATP then exposed to cholinergic, Alpha and Beta adrenergic or peptidergic agents. Secretory responses (in terms of release of K+, of amylase or as sialic acid liberated from secreted glycoproteins) will be measured at various times thereafter and correlated with changes in protein phosphorylation. In parallel studies, acini will be exposed to secretagogues in the presence of agents which inhibit, augment and/or mimic the effects of the second messengers in order to correlate changes in second messenger-dependent phosphorylation with changes in secretory response. These studies will yield new information concerning the mechanism of stimulus-secretion coupling in well-defined model exocrine systems and will provide new insights regarding the comparative physiology of secretory systems involved in a variety of diseases. In addition these studies will be important in defining the factors that regulate normal salivary gland function and therefore are important for the maintenance of healthy soft and mineralized tissue in the oral cavity.