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Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of the light-darkness cycle on the efficiency of the ultimobranchial and parathyroid glands in altering duodenal calcium transport and plasma and urinary concentrations of calcium was examined in the adult male frog (Rana pipiens). Frogs were unfed, but were allowed access to 0.05 M-CaCl2 in the surrounding medium after ultimobranchialectomy or parathyroidectomy. Calcium transport, as assayed by the everted gut-sac technique, was increased in ultimobranchialectomized frogs at sunrise, concomitant with acute hypercalcaemia and hypercalciuria. An opposite but chronic response was observed in parathyroidectomized frogs with intact ultimobranchial glands. The maximum response observed at sunrise occurred when the concentration of calcium in the plasma of control frogs was decreasing; the minimum response, which occurred 6 h after sunrise, was coincident with a diurnal peak in the concentration of calcium. Vitamin D3 (500 microgram/frog) enhanced calcium transport in ultimobranchialectomized frogs, which resulted in chronic hypercalcaemia and hypercalciuria. The results suggest that diurnal variations in the plasma concentration of calcium do not initiate ultimobranchial activity, but are a response to endocrine control synchronized with the transition from darkness to light.
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PMID:Diurnal variations in the influence of the ultimobranchial glands on calcium homeostasis in the frog (Rana pipiens). 21 89

Comparison of the mechanism of action Vitamin D3 and 1 alpha-OH D3 under conditions of experimental hypercalcemia. Acta Physiol. Pol. 1979, 30 (2): 313--318. The hypercalcemic effect of supraphysiological doses of Vitamin D and 1 alpha-OH D3 were compared applying an animal model. Changes in serum calcium of animals with normal dietary calcium supplementation and those under conditions of calcium depletion were analyzed. Dietary calcium is necessary for the hypercalcemic effect of Vitamin D, whereas in case of 1 alpha-OH D3 calcium is mobilized not only from the dietary but also from some other sources. The analysis of the hypercalcemia kinetics in the Vitamin D and 1 alpha-OH D3 treated animals indicated that the kidney 1 hydroxylase of 25 hydroxycholecalciferol is an important step in the hypercalcemia preventing mechanism.
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PMID:Comparison of the mechanism of action of vitamin D3 and 1 alpha-OH D3 under conditions of experimental hypercalcemia. 22 75

Administration of 500 mug vitamin D2 or D3 with ingestion of calcium to ultimobranchialectomized (UBX) or UBX-parathyroidectomized (PTX) frogs (Rana pipiens) induced hyerpcalcemia and hypercalciuria not apparent in control or PTX frogs. Calcium transport in isolated everted gut sacs was significantly elevated in UBX and UBX-PTX frogs but not in controls or PTX animals. Further, with Vitamin D3 in UBX frogs the duodenal segment had a greater capacity to transport calcium than the jejunal-ileal segment when compared to control, PTX or UBX-PTX frogs. Dihydrotachysterol2 and calcium ingestion also induced hypercalcemia, hypercalciuria and increased calcium transport in gut of UBX and UBX-PTX frogs, with no change seen in PTX or controls after 5 days. The inhibitory influence of the ultimobranchial glands on intestinal calcium transport apparently does not require the presence of the parathyroids and exhibits an inhibitory influence against a high calcium gradient across the duodenal segment.
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PMID:Effects of the ultimobranchial and parathyroid glands and vitamins D2, D3 and dihydrotachysterol2 on blood calcium and intestinal calcium transport in the frog. 107 5

Freshwater catfish, Heteropneustes fossilis, were injected daily intraperitoneally either with vehicle (0.05 ml of 95% ethanol/100 g body wt) or vitamin D3 (50 I.U./100 g body wt) and maintained in artificial fresh water, calcium-rich fresh water, or calcium-deficient fresh water for 10 days. The specimens were sacrificed on Days 1, 3, 5, and 10 after initiation of the experiment. The blood samples were collected on these intervals and serum calcium and inorganic phosphate levels were analyzed. Vitamin D3 induced hypercalcemia and hyperphosphatemia in the freshwater catfish, H. fossilis. These effects of vitamin D3 are not dependent upon the calcium concentration of the different ambient media used in this study.
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PMID:Effect of vitamin D3 administration on the serum calcium and inorganic phosphate levels of the freshwater catfish, Heteropneustes fossilis, maintained in artificial fresh water, calcium-rich fresh water, and calcium-deficient fresh water. 132 May 83

Vitamin D3, 25(OH) vitamin D3 and 1,25 (OH)2D3 were administered daily to unfed male Bufo andersoni for 15 days which resulted in a significant hypercalcemia and hyperphosphatemia in a dose-dependent fashion. 1,25(OH)2D3 is more potent than the other metabolites. The treatment activated ultimobranchial gland but induced degenerative changes in parathyroid of the toads.
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PMID:Dose-dependent vitamin D3, 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3-induced hypercalcemia and hyperphosphatemia, and the correlative changes in the activity of ultimobranchial and parathyroid glands of the toad, Bufo andersoni Boulenger. 133 66

Vitamin D3 administered to patients with postoperative hypoparathyroidism increases calcium absorption from the gut and calcium blood levels but leads to hypercalciuria and may produce renal lithiasis. Thiazides decrease calcium excretion with the urine. Therefore, an effect of combined therapy with hydrochlorothiazide, vitamin D3 and calcium on hypoparathyroidism was investigated. Twenty one women were selected out of 135 patients with postoperative hypoparathyroidism. These women were constantly given vitamin D3 (30,000-225,000 IU daily) and calcium. Normocalcemia, hyperphosphatemia and hypercalciuria were noted before the treatment with hydrochlorothiazide. Therapy normalized hypercalciuria but did not change mean differences in calcemia, phosphatemia, magnesemia, blood alkaline phosphatase and phosphates and magnesium clearance factors. Hypercalcemia and necessity to withdraw hydrochlorothiazide together with change of either doses or preparation of vitamin D3 were noted in three patients, including one patient in whom both hypercalcemia and hypercalciuria with the symptoms of vitamin D3 poisoning were observed. The author suggests that combined therapy with hydrochlorothiazide, vitamin D3 and calcium prevents hypercalciuria but may require changes in vitamin D3 dosage and withdrawal of hydrochlorothiazide in some patients.
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PMID:[Effect of hydrochlorothiazide on calcium metabolism in postoperative hypoparathyroidism]. 196 53

In two patients suffering from hypoparathyroidism (HP) whose serum calcium and -phosphate could not be normalized with Vitamin D3-resp. Calcitriol and who continued to have tetanic convulsions, synthetic 1-38 human parathyroid hormone (1-38 hPTH) was used for treatment. In both patients the intravenous administration of 1-38 hPTH provoked a rapid increase of phosphaturia and cAMP-excretion and an increase of the serum calcium level into the normal range. The same effects, only slightly delayed, could be achieved with subcutaneous injections which the patients had learned to do themselves. In case 1, a boy aged 14 years with autoimmune-HP, the daily administration of 8.5 U/kg BW caused hypercalcemia on the 6th day of treatment; therefore the dosis was reduced to alternate day administration. In case 2, a girl aged 17 1/2 years with idiopathic HP, treatment was started with alternate day administration (7.7 U/kg BW/day of injection); serum calcium increased to levels of about 2.2 mmol/1. Side effects could not be seen. Case 1, however, developed resistance to 1-38 hPTH after 10 weeks of therapy. 1-38 hPTH can be classified as an effective substance in the treatment of HP. Optimal dose and frequency of administration cannot yet be pointed out.
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PMID:[Initial experiences with substitution treatment of hypoparathyroidism with synthetic human parathyroid hormone]. 216 6

Vitamin D3 in the presence of calcium lactate induced significant hypercalcemia and hyperphosphatemia while calcitonin in the presence of a chelating agent (EGTA) induced hypocalcemia and hypophosphatemia in the rat lens. The physiologic significance of these changes in relation to cataract formation was understood by correlating the ratio of calcium and phosphate in the rat lens with the similar ratio obtained from human cataractous lenses of cortical and nuclear types.
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PMID:Vitamin D3 and calcitonin-induced regulation of calcium and phosphate in rat lens--its significance in cataract formation. 254 57

The activity of 18 vitamin D analogs on soft tissue calcification and growth impairment in neonatal rats and their effect on bone calcium mobilization, intestinal calcium absorption and binding to intestinal 1,25-dihydroxyvitamin D3 receptors in adult rats were compared. Depending on the chemical modification of the vitamin D parent compounds, they could be separated into active and inactive analogs. Cholecalciferol and ergocalciferol were similarly active, but epimerization of ergocalciferol at carbon 23 caused loss of activity. Hexafluorination at carbon 26 and 27 and the introduction of a double bond at carbon 22 or 23 had no or little effect on the activity. The loss of activity was caused by the introduction of a triple bond at carbon 23 and by hydroxylation at carbon 23, 26 or 28. The differentiation of human promyelocytic leukemia cells (HL-60) induced by these derivatives was used as a parameter for antitumour activity. All six analogs, which markedly affected calcium metabolism, were highly active in HL-60 cells. However, at least three derivatives were highly active in the antitumour test but failed to induce hypercalcemia. Thus, these results indicate that it could be possible to develop medically useful vitamin D derivatives devoid of hypercalcemic side-effects.
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PMID:Effects of vitamin D derivatives on soft tissue calcification in neonatal and calcium mobilization in adult rats. 255 50

The effects of WR-2721 [S-2-(3-aminopropylaminoethyl)phosphorothioic acid] in two in vivo and in vitro models of experimental hypercalcemia in the rat were examined. Chronic WR-2721 administration by osmotic minipump (250 mg/kg/24 hr) reduced serum calcium from 12.0 +/- 0.1 to 9.5 +/- 1.0 mg/dl (P less than .01) in rats receiving 1,25-(OH)2 Vitamin D3. Control rats receiving Vitamin D without WR-2721 had a rise in serum calcium to 13.4 +/- 0.2 mg/dl over the same 5-day period. In an experimental form of humoral hypercalcemia of malignancy, the Walker carcinosarcoma tumor-implanted rat, WR-2721 reduced serum calcium from 13.6 +/- 0.3 to 8.4 +/- 0.6 mg/dl by 5 to 6 days (P less than .001). In vitro bone resorption assays utilizing fetal rat long bones in organ culture showed complementary results. WR-2721 (10(-4) M) blocked bone resorption (assayed as percentage of 45Ca release) induced by both conditioned medium derived from cell lines of Walker carcinosarcoma (7.6 +/- 1.4 vs. 24.0 +/- 1.8%, P less than .01) and by addition of 1,25-(OH)2 Vitamin D3 (10(-8) M) (9.8 +/- 0.8 vs. 17.3 +/- 1.0%, P less than .01). These results suggest that WR-2721 may be effective in controlling clinical hypercalcemia due to excess bone resorption.
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PMID:In vivo and in vitro effects of WR-2721 in experimental hypercalcemia in the rat. 301 29


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