Stimulation of 24,25-Dihydroxyvitamin D3 Production by 1,25-Dihydroxyvitamin D3

Science  22 Mar 1974:
Vol. 183, Issue 4130, pp. 1198-1200
DOI: 10.1126/science.183.4130.1198


Vitamin D-deficient rats produce [3H]1,25-dihydroxyvitamin D3 from [3H]25-hydroxyvitamin D3 regardless of dietary content of calcium or phosphate. A daily dose of 130 picomoles of 1,25-dihydroxyvitamin D3 for a period of 5 days reduces production of [3H]1,25-dihydroxyvitamin D3 to essentially zero and stimulates production of [3H]24,25-dihydroxyvitamin D3. A daily dose of 325 picomoles of 25-hydroxyvitamin D3 has a similar but less dramatic effect. On the other hand, 650 picomoles daily of 24,25-dihydroxyvitamin D3 given to vitamin D-deficient rats had no effect. Thus it appears that 1,25-dihydroxyvitamin D3 is an important factor in the regulation of kidney metabolism of 25-hydroxyvitamin D3.

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