• Corpus ID: 20386425

Physiology of Vitamin D and Calcium Homeostasis

@inproceedings{Fraser2006PhysiologyOV,
  title={Physiology of Vitamin D and Calcium Homeostasis},
  author={David R. Fraser},
  year={2006}
}
In the past 20 years a voluminous literature has been written on the role of vitamin D in calcium homeostasis. This outpouring of experimental findings stemmed from the discovery that vitamin D was the precursor of a steroid hormone, 1,25-dihydroxyvitamin D [1,25(OH)2D], which affects calcium transport across cell membranes (1-4). Knowledge of the function of this steroid hormone now explains the observation of Nicolaysen, 50 years ago, that calcium absorption by the small intestine was… 

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References

SHOWING 1-10 OF 58 REFERENCES

Evidence that calcitonin stimulates 1,25-dihydroxyvitamin D production and intestinal absorption of calcium in vivo.

TLDR
Calcitonin and calcium are independent regulators of 1,25(OH)2D production and that calcitonin stimulates intestinal absorption of calcium, by increasing circulating levels of 1-25-dihydroxyvitamin D, respectively.

Role of vitamin D-dependent and vitamin D-independent mechanisms in absorption of food calcium.

TLDR
Net calcium absorption and the calcium content of the digestive glands secretions in people with widely different serum concentrations of 1,25 dihydroxy vitamin D are measured to mean that the D-dependent mechanism is saturated or nearly saturated by low calcium meals.

Evidence that calcium modulates circulating 25‐hydroxyvitamin D in man

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    Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research
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TLDR
Evidence is provided that changes in calcium intake can modulate the metabolism of 25‐OHD in man and alter the response of serum 25-OHD to challenge with vitamin D.

Vitamin D and Hyperparathyroidism

  • S. Stanbury
  • Medicine, Biology
    Journal of the Royal College of Physicians of London
  • 1981
TLDR
It is shown that the level of serum 25-(OH)D may always exert some influence on the production of 1,25-0(OH)2D and that this effect is facilitated by hyperparathyroidism.

Renal actions of vitamin D in D-deficient rats.

TLDR
The experiments were performed in rats since vitamin D deficiency can be produced in these animals in a comparatively short time, and because a normocalcemic state can be maintained in spite of D deficiency (25).

Effect of calcium intake on serum levels of 25‐hydroxyvitamin D3

TLDR
It is indicated that calcium intake is of some importance for the serum level of 25‐hydroxyvitamin D3, in agreement with previous studies in rats and in relation to the previous finding that there is a relationship between high 25‐Hydroxyv vitamin D3 levels and hypercalciuria in renal‐stone formers.

Dietary calcium and serum 1,25-(OH)2-vitamin D concentrations as determinants of calcium balance in healthy men.

TLDR
When serum 1,25-(OH)2-D levels are elevated, the availability of dietary Ca appears to prevent more negative Ca balances and increased urinary hydroxyproline excretion suggesting that net bone resorption is not stimulated.

Effect of growth hormone administration: reciprocal changes in serum 1 alpha,25-dihydroxyvitamin D and intestinal calcium absorption.

TLDR
The data suggest that GH does not directly influence parathyroid hormone or vitamin D metabolism, and the possibility that relative intestinal resistance to 1,25-dihydroxyvitamin D exists in patients with GH deficiency is considered.

Demonstration that circulating 1 alpha, 25-dihydroxyvitamin D is loosely regulated in normal children.

TLDR
Evidence is provided that circulating 1 alpha, 25(OH)2D is not as tightly regulated in children as it is in adults, and this difference in regulation could account in part for the higher values for serum 1alpha, 25-OH-2D observed in children.
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