SECOND MESSENGER FUNCTION IN EXOCRINE GLANDS

唾液腺和胰腺的分泌机制需要 CA2和环核苷酸，但这第二个的确切作用 信使及其胞浆浓度的调节只是 部分地理解了。这些研究将评估这一假设 第二信使浓度的控制在一定程度上是由第二信使 信使们自己。这一假设将在比较中得到检验。 大鼠颌下腺腺泡标本的研究及临床应用 胰腺作为模型系统来(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CaATPase与活性钙转位、腺苷和 鸟苷环化酶活力与cAMP、cGMP磷酸二酯酶 活动；以及(2)表征以下形式的动力学特性 那些受钙-钙调蛋白复合体调节的酶。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。 外分泌腺的活动，并评估分泌物 依赖于第二信使调节的蛋白质磷酸化。 将使用聚丙烯酰胺凝胶电泳法和放射自显影技术 检测和鉴定受调节的激酶的磷酸化底物 由破碎的腺泡细胞中的第二信使。在其他研究中， 功能性腺泡制剂将与P32孵育以标记 然后细胞内ATP暴露于胆碱能、α和β肾上腺素能或 肽能剂。分泌反应(以释放K、 淀粉酶或从分泌的糖蛋白中释放的唾液酸)将是 在之后的不同时间进行测量，并与蛋白质的变化相关 磷酸化。在平行研究中，阿奇尼将暴露于 在存在抑制、增强和/或模仿的试剂的情况下的促分泌剂 第二个信使的影响，以便关联变化 第二信使依赖的磷酸化与分泌的变化 回应。这些研究将提供有关 明确模型外分泌中刺激-分泌耦合的机制 系统，将提供关于比较生理学的新见解 涉及多种疾病的分泌系统。此外，还包括 研究对于确定调节正常的因素将是重要的。 唾液腺的功能，因此是重要的维持 口腔内健康的软组织和矿化组织。

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.