Evidence of a probable role for 25-hydroxyvitamin D in the regulation of human calcium metabolism.
Evidence of a probable role for 25-hydroxyvitamin D in the regulation of human calcium metabolism.
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25-羟基维生素 D 在调节人体钙代谢中可能发挥作用的证据。
DOI：
10.1002/jbmr.5650030503
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Shaw,S
中科院分区：
文献类型：
--
作者：
Bell,NH;Epstein,S;Shary,J;Greene,V;Oexmann,MJ;Shaw,S
1,25‐Dihydroxyvitamin D [1,25‐(OH)2D] is the principal mediator of the biologic effects of vitamin D. We showed previously that obese white subjects have low serum vitamin D and 25‐hydroxyvitamin D (25‐OHD) with increased serum‐immunoreactive parathyroid hormone (PTH) and 1,25‐(OH)2D, low urinary calcium, and increased urinary cyclic adenosine 3′,5′‐monophosphate (cyclic AMP) compared with nonobese white individuals. To determine whether 25‐OHD modulates calcium metabolism, the effects of 25‐OHD3, 40–100 μg/day for 9 days, were compared in seven obese and seven nonobese white subjects who were between the ages of 20 and 34 years. Each of them was hospitalized on a metabolic ward and given a constant daily diet that contained 400 mg calcium, 900 mg phosphate, and 18 mEq magnesium. Whereas 25‐OHD3increased mean serum 25‐OHD from 7 ± 1 to 37 ± 5 ng/ml (P< 0.01) and urinary calcium from 102 ± 18 to 146 ± 17 mg/day (P< 0.001) and decreased mean serum 1,25‐(OH)2D from 40 ± 2 to 28 ± 2 pg/ml (P< 0.01) and urinary cyclic AMP from 3.23 ± 0.57 to 2.00 ± 0.17 nM/dl GF (P< 0.05), it did not change mean serum calcium, ionized calcium, phosphate, magnesium, immunoreactive PTH or urinary phosphate, or creatinine clearance in the obese subjects. In contrast, 25‐OHD3increased mean serum 25‐OHD from 16 ± 1 to 46 ± 4 pg/ml (P< 0.001) but did not alter mean serum 1,25‐(OH)2D or urinary calcium or cyclic AMP in the nonobese subjects. Metabolic balance studies carried out in two of the obese subjects showed that 25‐OHD3increased serum 25‐OHD and urinary calcium and lowered serum 1,25‐(OH)2D. The findings are interpreted to mean that elevated serum 1,25‐(OH)2D and urinary cyclic AMP and low urinary calcium in obese subjects result from a deficiency of vitamin D and 25‐OHD, that these changes are reversed by 25‐OHD3, and that in humans 25‐OHD has a modest role in the regulation of calcium metabolism that is independent of the regulation by 1,25‐(OH)2D.
