Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0221002 (primary hyperparathyroidism)
 4,921 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twelve parathyroid chief cell adenomas from patients with primary hyperparathyroidism were incubated in a tissue culture system in the presence of different calcium concentrations and for various time periods. The endocrine response of the tissue was examined electron microscopically and radioimmunologically. After incubation in a medium of low calcium concentration the parathyroid adenomas showed ultrastructural signs of stimulation with proliferation of the hormone-synthesizing organelles. The development of the ultrastructural response could first be observed after four hours and increased up to several days. Radioimmunologically, an increase of the hormone secretion could be demonstrated. Converse results were obtained after incubation of the tumor tissue under suppressive culture conditions. To check for de-novo synthesis of the hormone released the tissue was incubated in a 75Se-methionine-containing medium. This resulted in radioactivity of the secreted parathyroid hormone, indicating de novo synthesis in our culture system. The biological potency of the released hormone was demonstrated by comparison of the PTH out of the medium with the international human MRC standard using two different radioassays.
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PMID:Correlation of electron microscopic and secretory response of human parathyroid adenomas with different calcium concentrations in organ culture. 15 Jan 11

1. Normal subjects showed a highly reproducible, rapid increase in plasma adenosine 3':5'-cyclic monophosphate (cyclic AMP) after an intravenous injection of 200 MRC units of highly purified bovine parathyroid hormone. 2. No significant increase in plasma cyclic AMP was observed after administration of bovine parathyroid hormone to patients with severe chronic renal failure. 3. Even when renal function was not impaired, some patients with primary hyperparathyroidism, who had high concentrations of endogenous parathyroid hormone, showed resistance to bovine parathyroid hormone and when this was injected intravenously it caused only a small increase in plasma cyclic AMP. This resistance was reversible since there was marked improvement in the response after parathyroidectomy, when endogenous parathyroid hormone concentration had fallen. 4. It was possible to reproduce this resistance to the hormone by intravenous infusion of bovine parathyroid hormone into normal subjects. When the hormone (1000 MRC units) was infused over 2 h, after an initial increase there was a progressive decline in plasma cyclic AMP concentration and a fall in urinary cyclic AMP excretion. The response to a standard test stimulus (200 MRC units of bovine parathyroid hormone given as a rapid intravenous injection) was examined at intervals after 1000 units of bovine parathyroid hormone had been infused. Initially, the response was severely impaired; at 4 h, partial recovery had occurred and, 24 h after the infusion, recovery of the response was complete. The resistance was therefore reversible. Infusion of the amino-terminal peptide, fragment 1-34, gave the same effect as infusion of intact hormone. Region-specific assays for the hormone were used to show that the concentration of immuno-assayable hormone remained high during the infusions. 5. The mechanism of this reversible resistance to parathyroid hormone remains to be elucidated; it seems unlikely that circulating hormone fragments could account for the prolonged impairment in the responsiveness to the intact hormone. It is possible that alteration in the formation, intracellular degradation or, perhaps, release of cyclic AMP from the cells, is the cause. Changes in the characteristics of the hormone receptor sites might also explain the phenomenon.
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PMID:Reversible resistance to the renal action of parathyroid hormone in man. 18 Nov 94

The authors measured the degree of hypocalcaemia (delta Ca S), hypophosphataemia and the fall in urinary hydroxyproline excretion induced by an intramuscular injection of 100 MRC U of synthetic salmon calcitonin (S.C.T.) during the 24 hours following the injection. In 15 control subjects, the fall in plasma calcium was slight ( - 2.1 +/- 0.9 mg/l) but significant. In bone diseases involving hyperosteoclastosis, the degree of hypocalcaemia was much greater: 10.6 +/- 1.1 mg/l in 24 cases of Paget's disease, - 9.0 +/- 1.6 mg/l in 5 cases of diffuse malignant disease of bone, - 8.0 +/- 1.4 mg/l in 6 cases of primary hyperparathyroidism and - 3.5 +/- 0.8 mg/l in 13 cases of algodystrophy of the limbs. In the subjects studied as a whole there was a significant linear relationship between the delta Ca S and the extent of the trabecular surfaces of osteoclastic resorption, but not between delta Ca S and total 24 hour urinary hydroxyproline excretion. The S.C.T. hypocalcaemia test would appear to be a simple means for the evaluation of osteoclastic activity within the skeleton, and thus to select those bone disorders which should respond to antiosteoclastic therapy (calcitonin, diphosphonates).
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PMID:[Induced hypocalcaemia test using salmon calcitonin as a means for the evaluation of osteoclastic activity (author's transl)]. 56 8

In order to investigate the effect of calcitonin (CT) on calcium and phosphorus metabolism in primary hyperparathyroidism (PHP), porcine calcitonin (80 MRC units) was injected intramuscularly at 9:00 a.m. and 5:00 p.m. for 10-14 days in 7 patients with parathyroid adenoma. Fasting blood specimens were drawn at 8:00 a.m. every other day and 24 hour urine samples were collected through out control and test days. To examine the acute effect of CT, blood and urine were checked several times until 8 hours after the first injection. A fall in the fasting serum calcium level observed in 5 patients during the repeated administrations of CT, as well as that observed in 6 patients within 6 hours after the first injection, showed a significant correlation with the initial serum calcium level. Serum phosphorus concentration decreased in all patients 6 hours after the first injection, while fasting levels seemed to remain unchanged. During the repeated administrations, urinary excretion of calcium and phosphrus decreased correspondingly with the fall in serum calcium levels, although no definite tendancy was observed within 8 hours after the first injection. Fasting serum PTH levels during the repeated administrations were measured in 2 patients. In a patient whose serum calcium returned to the initial level on the 7th day of administration, a gradual rise of PTH was observed, while in another patient whose serum calcium was kept lower than the initial level, PTH remained almost unchanged. These results indicate that, under such a condition where there is marked increase of bone resorption as PHP, repeated administrations of CT bring about not only a hypocalcemic effect but also the reduction of calcium and phosphorus excretion through a decreased filtered load. In addition, it was suggested that, in some cases of PHP, the hypocalcemic effect of CT may be abolished by an increase of PTH secretion from the parathyroid glands during long-term administration.
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PMID:[Effect of porcine calcitonin in primary hyperparathyroidism (author's transl)]. 94 35

Experimental studies have suggested that in primary hyperparathyroidism (HPT) the cells of the hyperfunctioning parathyroid tissue retain some capacity for stimulation and that an increase in secretion of parathyroid hormone (PTH) can occur when the extracellular calcium concentration is lowered within the hypercalcaemic range. We have tested this hypothesis in 23 patients with HPT, 10 patients with hypercalcaemia of other origin (7 of whom had disseminated malignant disease) and 17 normal subjects. In all three groups a single injection of 100 MRC units of salmon calcitonin caused a reduction in serum calcium of approximately 3 to 5%. In the hypercalcaemic patients this reduction was correlated to the basal calcium level (r = -0.57, P less than 0.01). In the patients with HPT, although they all remained hypercalcaemic, the decrease in serum calcium was associated with a mean increase in serum PTH of 10%. Only in 2 patients did such an increase fail to occur despite an adequate decrease in serum calcium. These 2 patients had high basal PTH levels and the lack of response might have been due to a high degree of autonomous parathyroid function. Calcitonin also reduced serum calcium and increased serum PTH in normal subjects. None of the patients with hypercalcaemia of other origin than primary HPT displayed a secretory PTH response to serum calcium reduction. Thus, this test could be of practical clinical value, particularly in patients with borderline PTH values. A calcitonin-induced rise in PTH while serum calcium is lowered within the hypercalcaemic range strongly suggests primary HPT.
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PMID:A stimulation test with calcitonin for differential diagnosis of hypercalcaemia. 649 90

Urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) transiently increases after PTH(1-34) infusion in idiopathic hypoparathyroidism (IHP) but this response is impaired in pseudohypoparathyroidism (PHP) type I. We investigated the effects of endogenous PTH, exogenous calcitonin (CT), and dibutyryl cAMP (DBcAMP) on urinary excretion of NAG. Urinary NAG excretion in 14 patients with primary hyperparathyroidism (1 degree HPT) was more than in normal subjects (P < 0.001) and decreased after parathyroidectomy (P < 0.01). Urinary NAG excretion increased after the infusion of 1.5 MRC/kg of eel CT in eight normal subjects (P < 0.001), two patients with IHP, and a patient with PHP type Ib but not in a patient with PHP type Ia. The increases of urinary NAG excretion by CT and by PTH(1-34) were positively correlated with the increases of urinary cAMP excretion (r = 0.752; P < 0.001 and r = 0.534; P < 0.002, respectively). Urinary NAG excretion increased after DB-cAMP infusion in five normal subjects (P < 0.01), two patients with IHP, and two with PHP type I. The increase of urinary NAG by 6.0 mg/kg of DBcAMP was more than by 2.5 mg/kg of DBcAMP in normal subjects (P < 0.01). The increase of urinary NAG by 2.5 mg/kg of DBcAMP in PHP type I was comparable with that by 6.0 mg/kg in normal subjects, suggesting a hyperresponsiveness to DBcAMP in PHP type I. Urinary excretion of NAG is a useful indicator of renal tubular responsiveness to PTH and CT. Cyclic AMP-dependent mechanism is probably involved in PTH and CT-induced increase in urinary excretion of NAG.
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PMID:The effect of endogenous parathyroid hormone, exogenous calcitonin, and dibutyryl cyclic AMP on urinary excretion of N-acetyl-beta-D-glucosaminidase. 805 64