1,25-DIHYDROXYVITAMIN D RECEPTOR/FUNCTION IN NEW TARGETS

本项目的总体目标是阐明功能(S) 1，25-二羟基维生素D3(1，25(OH)2D3)或其缺乏，在 通过解决假设的新的假定的靶组织 1，25(OH)2D3通过以下途径发挥特定而重要的作用 先前描述的受体。因此，1，25(OH)2D3函数将 通过一系列的生理和心理评估 模型大鼠心脏和睾丸的生化指标。 这些研究的第一阶段集中于测试 1，25(OH)2D3在细胞内钙离子中的作用假说 动态平衡。然而，由于限制这种情况的谬误 对可能函数的任何一个区域的研究，假设 1，25(OH)2D3通过交替的机制影响这些体系 在未来接受测试。两者之间是否存在相关性 维生素D或1，25(OH)2D3受体状态与生理功能 将通过评估维生素D状态的影响来测试 正常血压对大鼠心肌收缩特性的影响 和睾丸功能，并检查1，25(OH)2D3 推测的新靶组织中的受体水平与 维生素D内分泌系统的生理状态。效应 1，25(OH)2D3状态及其受体对细胞内钙的影响 心脏和支持细胞的动态平衡将通过以下方式进行评估 激素对体内摄取~(45)Ca影响的研究 培养的心肌细胞和支持细胞。1，25(OH)2D3的作用 关于选定的机制/亚细胞细胞器将由 大鼠心肌细胞和支持细胞摄取~(45)Ca的测定 没有或存在药理探针。其他研究 将扩展对1，25(OH)2D3状态/受体影响的研究 用~(45)CA结合蛋白质检测钙结合蛋白 转印迹到硝酸纤维素膜上，在受 通过125-I-钙调蛋白凝胶覆盖技术，以及通过 钙结合蛋白的免疫细胞化学定位 演示维生素D的调节作用。这些相互关联的研究 1，25(OH)2D3功能和受体在推测的新靶点将增加 我们对维生素D内分泌系统和 将为未来1，25(OH)2D3功能的评估提供基础 在正常和患病的个体中。

The overall goal of this project is to elucidate the function(s) of 1,25-dihydroxyvitamin D3(1,25(OH)2D3), or the lack thereof, in new putative target tissues by addressing the hypothesis that 1,25(OH)2D3, exerts specific and important effects therein via previously described receptors. Thus, 1,25(OH)2D3 function will be rigorously evaluated by a series of physiological and biochemical criteria in the model systems rat heart and testis. The first phases of these studies are focused on testing the hypothesis that 1,25(OH)2D3 plays a role in intracellular calcium homeostasis. However, because of the fallacy in limiting such studies to any one area of possible functions, the hypothesis that 1,25(OH)2D3 affects these systems through alternate mechanisms must be tested in the future. Whether there is a correlation between vitamin D status or 1,25(OH)2D3 receptor and physiological function will be tested by evaluating the effects of vitamin D status in normocalcemic rats on the contractile properties of heart muscles and on testicular function and examining whether 1,25(OH)2D3 receptor levels in putative new target tissues correlate with physiological status of the vitamin D endocrine system. Effects of 1,25(OH)2D3 status and receptors on intracellular calcium homeostasis in heart and Sertoli cells will be evaluated by studying the hormonal effects on uptake of 45Ca into intact cultured heart myocytes and Sertoli cells. Effects of 1,25(OH)2D3 on selected mechanisms/subcellular organelles will be evaluated by determining 45Ca uptake in heart myocytes and Sertoli cells in the absence and presence of pharmacological probes. Additional studies will extend studies of the effects of 1,25(OH)2D3 status/receptors on calcium binding proteins detected by 45CA binding to proteins transblotted to nitrocellulose membranes, on proteins modulated by calmodulin by the 125-I-calmodulin gel overlay technique, and by immunocytochemical localization of calcium binding proteins that demonstrate vitamin D regulation. These interrelated studies of 1,25(OH)2D3 function and receptors in putative new targets will add much to our understanding of the vitamin D endocrine system and will provide a basis for future assessments of 1,25(OH)2D3 function in both normal and diseased individuals.