Is 24,25-dihydroxycholecalciferol a calcium-regulating hormone in man?
نویسندگان
چکیده
Small doses (1-10 microgram daily) of 24,25-dihydroxycholecalciferol (24,25-(OH)2D3), a renal metabolite of vitamin D of uncertain function, increased intestinal absorption of calcium in normal people and in patients with various disorders or mineral metabolism, including anephric subjects. In five of six patients studied, calcium balance increased, but, unlike 1,25-dihydroxycholecalciferol, 24,25-(OH)2D3 did not increase plasma or urinary calcium concentrations. These results suggest that 24,25-(OH)2D3 may be an important regulator of skeletal metabolism in man with potential value as a therapeutic agent.
منابع مشابه
The absence of 24,25-dihydroxycholecalciferol in anephric patients.
1. In subjects with normal renal function there was a strong positive correlation between serum concentrations of 25-hydroxycholecalciferol and 24,25-dihydroxycholecalciferol, as measured by competitive protein-binding assay. 2. The 24,25-dihydroxycholecalciferol concentration was about 7% of the prevailing 25-hydroxycholecalciferol concentration. 3. In contrast, sera from anephric patients con...
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متن کاملSynthesis of 1,25-dihydroxycholecalciferol and 24,25-dihydroxycholecalciferol by calvarial cells. Characterization of the enzyme systems.
The synthesis of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] and 24,25-dihydroxycholecalciferol [24,25(OH)2D3] from 25-hydroxycholecalciferol [25(OH)D3] has previously been shown to occur in cells isolated from bone. The main findings of the present study are that the enzyme systems which catalyse these syntheses are: (1) active at 'in vitro' substrate concentrations over the range of 2-50 nM; ...
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عنوان ژورنال:
- British medical journal
دوره 1 6124 شماره
صفحات -
تاریخ انتشار 1978