Chapter title |
Physiological and pharmacological aspects of 24,25-dihydroxycholecalciferol in man.
|
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Chapter number | 49 |
Book title |
Homeostasis of Phosphate and Other Minerals
|
Published in |
Advances in experimental medicine and biology, January 1978
|
DOI | 10.1007/978-1-4684-7758-0_49 |
Pubmed ID | |
Book ISBNs |
978-1-4684-7760-3, 978-1-4684-7758-0
|
Authors |
Russell, R G, Kanis, J A, Smith, R, Adams, N D, Bartlett, M, Cundy, T, Cochran, M, Heynen, G, Warner, G T, Russell, R. G. G., Kanis, J. A., Smith, R., Adams, N. D., Bartlett, M., Cundy, T., Cochran, M., Heynen, G., Warner, G. T. |
Abstract |
The present study describes the response to small oral doses (1--10 microgram/day) of 24,25-DHCC in man. Contrary to expectation, 24,25-DHCC was as potent as 1,25-DHCC in increasing intestinal absorption of calcium both in normal persons and in patients with a variety of disorders of calcium metabolism. Despite this increase in intestinal absorption, plasma and urine calcium did not increase after 24,25-DHCC as they did after 1,25-DHCC. Metabolic balance studies showed calcium balances to increase by 1.6 to 11.5 mmoles/day in 5 of the 6 patients studied. 24,25-DHCC increased intestinal absorption of calcium equally well in anephric patients, suggesting that conversion of 24,25-DHCC to 1,24,25-trihydroxycholecalciferol by the kidney cannot be the sole mechanism by which 24,25-DHCC expresses biological activity, even though in vitamin D deficient rats nephrectomy does abolish the ability of large doses of 24,25-DHCC to increase calcium absorption. It is concluded that 24,25-DHCC may be a calcium-regulating hormone in man. In view of the effects demonstrated here and its relatively high concentration in plasma and slow turnover rate, 24,25-DHCC has the properties that might be ideal for a long-acting stimulator of bone mineralisation. Further work is needed to explain why 24,25-DHCC has effects in man which are not readily seen in other species. |
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Geographical breakdown
Country | Count | As % |
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Unknown | 2 | 100% |
Demographic breakdown
Readers by professional status | Count | As % |
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Student > Master | 1 | 50% |
Unknown | 1 | 50% |
Readers by discipline | Count | As % |
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Medicine and Dentistry | 1 | 50% |
Unknown | 1 | 50% |