THE ASSAY OF 1α, 25-DIHYDROXYVITAMIN D3: PHYSIOLOGIC AND PATHOLOGIC MODULATION OF CIRCULATING HORMONE LEVELS
| Autor: | S. J. Counts, Toni A. McCain, J. E. Wergedal, D. J. Bayklink, M. R. Hughes, R. L. Nielsen, Mark R. Haussler, Fu-Hsiung Shen, Kristine M. Bursac, P. F. Brumbaugh |
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| Rok vydání: | 1976 |
| Předmět: |
Male
medicine.medical_specialty Endocrinology Diabetes and Metabolism Thyroid Gland Parathyroid hormone Receptors Cell Surface Binding Competitive Phosphates Parathyroid Glands Radioligand Assay Endocrinology Internal medicine medicine Animals Homeostasis Humans Transplantation Homologous Renal osteodystrophy Intestinal Mucosa Pseudohypoparathyroidism Calcium metabolism Kidney Hydroxycholecalciferols Chemistry medicine.disease Kidney Transplantation Diet Rats medicine.anatomical_structure Hypoparathyroidism Dihydroxycholecalciferols Thyroidectomy Kidney Failure Chronic Calcium Parathyroid disorder Chickens Rickets Hormone |
| Zdroj: | Clinical Endocrinology. 5:s151-s165 |
| ISSN: | 1365-2265 0300-0664 |
| DOI: | 10.1111/j.1365-2265.1976.tb03823.x |
| Popis: | A sensitive radioreceptor assay for 1alpha,25-dihydroxyvitamin D3 (1alpha,25-(OH)2D3) is utilized to quantitate the circulating concentration of this sterol in experimental animals and humans. When weanling rats are grown for 2 weeks on low calcium or low phosphate diets, limited availability of either ion elicits a five-fold increase in the plasma level of 1alpha,25-(OH)2D3. The enhancement of 1alpha,25-(OH)2D3 in calcium deficiency is dependent upon the presence of the parathyroid and/or thyroid glands, which is consistent with parathyroid hormone (PTH) mediation of this effect. In contrast, the response to phosphate deficiency is independent of these glands and may result from a direct action of low phosphate on the renal synthesis of 1alpha,25-(OH)2D3. Studies in humans indicate that the normal level of 1alpha,25-(OH)2D is 2.1--4.5 ng/100 ml plasma. Patients with chronic renal failure have markedly lower circulating 1alpha,25-(OH)2D and this kidney hormone is undetectable in anephric subjects, but returns to normal within 1 day after successful renal transplantation. Hypoparathyroidism and pseudohypoparathyroidism are associated with reduced plasma 1alpha,25-(OH)2D while patients with primary hyperparathyroidism have significantly elevated sterol hormone levels. Thus, from measurements in rats and humans, it appears that circulating 1alpha,25-(OH)2D3 is regulated by PTH and/or phosphate and that abnormal plasma 1alpha,25-(OH)2D3 is a part of the pathophysiology of renal osteodystrophy and parathyroid disorders. |
| Databáze: | OpenAIRE |
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