Bollag R J, Zhong Q, Phillips P, Min L, Zhong L, Cameron R, Mulloy A L, Rasmussen H, Qin F, Ding K H, Isales C M
Institute of Molecular Medicine and Genetics, Department of Medicine, Medical College of Georgia, Augusta 30912, USA.
Endocrinology. 2000 Mar;141(3):1228-35. doi: 10.1210/endo.141.3.7366.
Glucose-dependent insulinotropic peptide (GIP) is a 42-amino acid peptide synthesized and secreted from endocrine cells in the small intestine. The role of GIP in coupling nutrient intake and insulin secretion, the incretin effect, is well known. We report that GIP receptor messenger RNA and protein are present in normal bone and osteoblast-like cell lines, and that high affinity receptors for GIP can be demonstrated by [125I]GIP binding studies. When applied to osteoblast-like cells (SaOS2), GIP stimulated increases in cellular cAMP content and intracellular calcium, with both responses being dose dependent. Moreover, administration of GIP results in elevated expression of collagen type I messenger RNA as well as an increase in alkaline phosphatase activity. Both of these effects reflect anabolic actions of presumptive osteoblasts. These results provide the first evidence that GIP receptors are present in bone and osteoblast-like cells and that GIP modulates the function of these cells.
葡萄糖依赖性促胰岛素多肽（GIP）是一种由小肠内分泌细胞合成并分泌的42个氨基酸的肽。GIP在营养摄入与胰岛素分泌偶联过程中的作用，即肠促胰岛素效应，是众所周知的。我们报告称，GIP受体信使核糖核酸和蛋白质存在于正常骨骼及成骨细胞样细胞系中，并且通过[125I]GIP结合研究可以证实存在GIP的高亲和力受体。当应用于成骨细胞样细胞（SaOS2）时，GIP刺激细胞内cAMP含量增加以及细胞内钙增加，这两种反应均呈剂量依赖性。此外，给予GIP会导致I型胶原信使核糖核酸表达升高以及碱性磷酸酶活性增加。这两种效应均反映了假定成骨细胞的合成代谢作用。这些结果提供了首个证据，表明GIP受体存在于骨骼及成骨细胞样细胞中，并且GIP调节这些细胞的功能。
