Effects of small iv doses of 1.25-dihydroxy- and 24.25-dihydroxy-vitamin D3 (a microgram) were studied in 10 normal subjects. Injection of 1.25 (OH)2D3 was associated with small but significant increases in plasma calcium and phosphate but plasma levels of immunoreactive parathyroid hormone (iPTH) and calcitonin (iCT) did not change. The administration of 24.25 (OH)2D3 was associated with comparable decreases in plasma calcium and a small and transient decrease in plasma iPTH. Plasma levels of iCT did not change. 24.25 (OH)2D3 also significantly increased glomerular filtration rate and decreased the urinary excretion of noradrenaline, in contrast to 1.25 (OH)2D3 which had no effect on these variables. The rapid infusion of calcium significantly decreased levels of iPTH. We conclude that small doses of 1.25 (OH)2D3 and 24.25 (OH)2D3 have little, if any, direct effect on the secretion of PTH and CT in man.
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http://dx.doi.org/10.1530/acta.0.0980619 | DOI Listing |
Zhonghua Nei Ke Za Zhi
February 2005
Institute of Endocrinology & Metabolism, the Second Xiangya Hospital of Central South Medical University, Changsha 410011, China.
Objective: To characterize the effects of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] on the expression of matrix metalloproteinase (MMP)-1, MMP-2, membrane-type MMP-1 (MT1-MMP), tissue inhibitors of metalloproteinase-1 (TIMP-1) in human osteoblast, and understand the mechanism by which 1alpha,25(OH)2D3 exert on bone.
Methods: Osteoblasts were interfered by 1alpha,25(OH2D3. Western blot were used to show the action of 1alpha,25(OH)2D3 on the expression of MT1-MMP protein in human osteoblasts.
Bone
February 2005
School of Clinical and Laboratory Sciences, The Medical School, Framlington Place, University of Newcastle, Newcastle upon Tyne, NE2 4HH, United Kingdom.
FK506 is a commonly used immunosuppressant that mediates its action by exclusively interacting with the cytosolic immunophilin, FK506 binding protein 12 (FKBP12). Although FK506-induced acute osteoporosis is now well recognised, its precise mode of action in osteoblasts remains unclear. Therefore, in the present study we characterised FKBP12 in osteoblasts and investigated the role of FK506 in modulating osteoblast-specific transcription factors, core-binding factor alpha1 (Cbfa1) and osterix gene expression in ROS 17/2.
View Article and Find Full Text PDFHypokinesia (diminished movement) induces phosphate (P) changes; however, it is not known if P change is greater in trained than untrained subjects. Measuring P balance and P retention during hypokinesia (HK) and P load, we studied if changes in P retention and P depletion were significantly (p<0.05) greater in trained than untrained subjects.
View Article and Find Full Text PDFPediatr Med Chir
October 1996
Dipartimento di Pediatria, Università di Firenze, Italia.
We describe a child with vitamin D dependent rickets type 1, who developed clinical signs of the disease at three months of age. The principal manifestations were hypocalcemia and seizure with EEG abnormalities. The circulating level of 1 alpha, 25 (OH)2D3 was low despite a normal level of 25 (OH)D3 and an adequate vitamin D supplementation.
View Article and Find Full Text PDFNihon Jinzo Gakkai Shi
July 1992
Second Department of Internal Medicine, Nippon Medical School.
It is said that maintenance hemodialysis patients are already suffering from secondary hyperparathyroidism (2HPT) from early stage of chronic renal failure. The treatment of 2HPT in this stage is very important for preventing renal osteodystrophy (ROD). But many long-term dialysis patients are still afflicted with ROD although vitamin D have been used for treatment.
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