Abnormalities in parathyroid hormone secretion and 1,25-dihydroxyvitamin D3 formation in women with osteoporosis

Article Abstract:

The role of parathyroid hormone in the metabolism of vitamin D in osteoporosis is examined. Three groups of subjects were included in the study: postmenopausal women with osteoporosis, women in the same age range (49 to 79 years) with no osteoporosis, and young women with no osteoporosis. The results of the study help to establish the relative effects of aging and osteoporosis on vitamin D metabolism. Parathyroid hormone stimulates an enzyme which converts vitamin D to its active form, 1,25-dihydroxyvitamin D(sub.3). This regulatory reaction is impaired in the aged and in cases of osteoporosis, resulting in reduced formation of the active vitamin D metabolite. A reduction in vitamin D metabolite is one of the primary causes of bone mineral loss in osteoporosis. When oral phosphate was administered to all three groups, all subjects experienced a rise in serum phosphate and a decrease in serum calcium, but changes in levels of parathyroid hormone and 1,25(OH)(sub.2)D varied. Both control groups experienced no change in levels of 1,25(OH)(sub.2)D while experiencing a rise in parathyroid hormone levels; the older women experienced a significantly higher rise. The osteoporotic subjects had a much smaller increase in parathyroid hormone and a drop in 1,25(OH)(sub.2)D level. Patients with osteoporosis do not appear to be able to produce an adequate parathyroid hormone response after stimulation to maintain the vitamin D homeostasis required to conserve bone mineral content. More work is needed to allow a more complete understanding of the role of abnormal vitamin D metabolism in osteoporosis.

Analysis, Laws, regulations and rules, Causes of, Physiological aspects, Diseases, Parathyroid hormone, Parathyroid hormones, Secretion, Osteoporosis, Vitamin D, Aged women, Elderly women, Vitamin metabolism, Vitamin D metabolism

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A 10-year prospective study of primary hyperparathyroidism with or without parathyroid surgery

Article Abstract:

Many patients with primary hyperparathyroidism may benefit from surgery even if they have no symptoms. Hyperparathyroidism is characterized by high blood levels of parathyroid hormone and excessive blood levels of calcium. Researchers followed 121 people with primary hyperparathyroidism, 83% of whom had no symptoms. Half had their parathyroid glands removed and half did not. Calcium levels returned to normal in those who had surgery and their bones became stronger. One-fourth of those who did not have surgery experienced a progression of their disease and were also more likely to develop kidney stones.

Prognosis, Surgery, Parathyroid glands, Parathyroidectomy

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Short-term inhibition of parathyroid hormone secretion by a calcium-receptor agonist in patients with primary hyperparathyroidism

Article Abstract:

A drug that mimics the effect of calcium on receptors in the parathyroid gland can reduce hormone secretion and high calcium levels in hyperparathyroidism, and may provide the basis for nonsurgical treatment of the disease. The parathyroid hormone regulates the level of calcium in the body. A range of doses of the drug R-568 in 20 patients reduced parathyroid hormone concentration 26% to 51% and lowered blood calcium levels. This drug is the first to directly affect hormone secretion in this disease, and these results may be a basis for treatment.

Drug therapy

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