Naveh-Many T, Raue F, Grauer A, Silver J
Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah University Hospital, Jerusalem, Israel.
J Bone Miner Res. 1992 Oct;7(10):1233-7. doi: 10.1002/jbmr.5650071016.
High calcium leads to the secretion of calcitonin, and the administration of 1,25-dihydroxyvitamin D3 leads to a decreased transcription of the calcitonin gene. We now report the effect of chronic hypercalcemia, hypocalcemia, and vitamin D deficiency on calcitonin gene expression in vivo in the rat. Hypercalcemia was created by calcium infusions for 6 h, a high-calcium diet given to weanling rats for 3 weeks, and the transplantation of the Walker carcinosarcoma 256 cell line. Despite serum calcium as high as 22 mg/dl, there was no difference in calcitonin mRNA levels among these rats. The control genes studied, actin and somatostatin, which is specific for C cells in the thyroparathyroid tissue, also did not differ among the different groups of rats. Injected 1,25-(OH)2D3 decreased calcitonin mRNA levels at 6 h, as previously reported. Hypocalcemia, created by feeding diets deficient in calcium and vitamin D to weanling rats for 3 weeks, had no effect on calcitonin mRNA levels, in contrast to the large increases in PTH mRNA levels. These results demonstrate that calcitonin gene expression in vivo in the rat is regulated by administered 1,25-(OH)2D3 but not by changes in serum calcium.
高钙会导致降钙素的分泌，而给予1,25 - 二羟基维生素D3会导致降钙素基因的转录减少。我们现在报告慢性高钙血症、低钙血症和维生素D缺乏对大鼠体内降钙素基因表达的影响。通过静脉输注钙6小时、给断奶大鼠喂食高钙饮食3周以及移植沃克癌肉瘤256细胞系来制造高钙血症。尽管这些大鼠的血清钙高达22mg/dl，但它们之间的降钙素mRNA水平并无差异。所研究的对照基因，即肌动蛋白和对甲状旁腺组织中C细胞特异的生长抑素，在不同组的大鼠中也没有差异。如先前报道的那样，注射1,25 - (OH)2D3在6小时时会降低降钙素mRNA水平。通过给断奶大鼠喂食缺乏钙和维生素D的饮食3周制造的低钙血症，对降钙素mRNA水平没有影响，这与甲状旁腺激素（PTH）mRNA水平的大幅升高形成对比。这些结果表明，大鼠体内的降钙素基因表达受给予的1,25 - (OH)2D3调节，而不受血清钙变化的调节。
