ACTIONS OF CALCIUM REGULATING HORMONES IN THE GUT

这项工作涉及的总体假设是钙调节 激素肽，尤其是甲状旁腺激素和降钙素 基因相关肽(CGRP)在肠道调节中的重要作用 功能。甲状旁腺素是一种高效的胃肠道平滑肌松弛药。这 该项目将详细研究GI甲状旁腺素受体的性质和 牵涉到的第二个信使。大鼠胃肠道平滑肌和粘膜将被 利用标准配基结合技术进行研究，受体化学交叉 链接和放射自显影，以便比较GI受体和经典受体 甲状旁腺激素受体在骨和肾脏中的定位及其特异性 胃肠道细胞。第二个要检查的信使包括环核苷酸， 细胞内钙离子和肌醇磷酸盐。还讨论了 假设甲状旁腺素相关蛋白(PTHrP)，一种新发现的肿瘤- 与恶性体液高钙血症有关的衍生肽 通常在胃肠道粘膜或肌肉细胞中，局部起旁分泌或 调节胃肠道事件的自分泌因子。分子生物技术 将被用来在肠道中搜索PTHrP mRNA，并通过原位 杂交组织化学，将mRNA定位于特定的GI细胞。 免疫细胞化学将同时用于定位PTHrP本身。 发育变化与妊娠、哺乳、衰老和 将检查伤口愈合情况。的生理学意义 甲状旁腺素样肽在肠道中的作用将通过研究来检验 体内不可吸收标志物测定对大鼠肠道的影响 这些多肽对胃肠动力的影响。CGRP，也是已知的影响胃肠道功能的物质， 特别是收缩性能，也将使用这些方法进行研究 为PTHrP概述。大鼠和猪胃肠道组织中的受体将是 特征，第二个信使将被识别，并且本地化 和肽本身将用杂交和 免疫细胞化学技术。这些研究将有助于阐明 PTHrP是一种与血管紧张素转换酶功能相关的新肽，其生理意义 仅存在于肿瘤组织中。这项工作最终应该建立新的 钙相关多肽在肠道中的作用，阐明涉及的机制， 促进我们对它们在健康和疾病中的作用的了解，并使 美国使用这些多肽或其类似物作为治疗剂。

The overall hypothesis addressed in this work is that Ca-regulatory hormonal peptides, especially parathyroid hormone (PTH) and calcitonin gene-related peptide (CGRP), play important roles in regulation of gut function. PTH is a highly effective relaxant of GI smooth muscle. This project will examine in detail the nature of the GI PTH receptors and the second messengers involved. Rat GI smooth muscle and mucosa will be studied using standard ligand binding techniques, receptor chemical cross- linking, and autoradiography in order to compare GI receptors to classical PTH receptors in bone and kidney and to localize the receptors to specific GI cells. Second messengers to be examined include cyclic nucleotides, intracellular Ca++, and inositol phosphates. Also addressed is the hypothesis that PTH-related protein (PTHrP), a newly discovered tumor- derived peptide involved in humoral hypercalcemia of malignancy, is present normally in GI mucosal or muscle cells and acts locally as a paracrine or autocrine factor to regulate GI events. Molecular biological technology will be used to search for PTHrP mRNA in the gut and, by in situ hybridization histochemistry, to localize the mRNA to specific GI cells. Immunocytochemistry will be employed concurrently to localize PTHrP itself. Developmental changes in association with gestation, lactation, aging, and wound healing will be examined. The physiological significance of the effect of PTH-like peptides in the gut will be examined by studying nonabsorbable markers in vivo in the rat gut to determine the influence of these peptides on GI motility. CGRP, also known to affect GI function, especially contractility, also will be studied using the approaches outlined for PTHrP. Receptors in rat and pig GI tissue will be characterized, second messengers will be identified, and the localization of mRNA and the peptide itself will be studied using hybridization and immunocytochemical techniques. The studies will help elucidate the physiological importance of PTHrP, a new peptide functionally associated at present only with tumor tissue. The work ultimately should establish new roles for Ca-related peptides in the gut, clarify the mechanisms involved, promote our understanding of their roles in health and disease, and enable us to employ these peptides or their analogs as therapeutic agents.