Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The normal fractional urinary excretion of filtered magnesium is about 5%. In magnesium deficiency in man, the kidneys can normally reduce the 24-hour urinary magnesium excretion to less than 1 mmol (24 mg) via unknown mechanisms, and initially without a fall in plasma magnesium concentration. Renal magnesium wasting may be defined as a urinary excretion greater than 1 mmol/day in the presence of hypomagnesemia (plasma magnesium < 0.7 mmol/l). Congenital renal magnesium wasting occurs in several syndromes including Bartter's syndrome in which it is associated with hypercalciuria, and the defect may be in the thick ascending limb of Henle's loop, and Gitelman's syndrome in which there is hypocalciuria, and the defect may be in the distal convoluted tubule. Other causes of renal magnesium wasting include diabetes mellitus, hypercalcemia and diuretics. Magnesium wasting may also result from various toxicities including those of cis-platinum, in which the biochemical features resemble Gitelman's syndrome, and those of aminoglycosides, pentamidine and cyclosporin. Calcitriol deficiency may also contribute to renal magnesium wasting in some circumstances. Mild hypermagnesemia may occur in familial hypocalciuric hypercalcemia and may reflect abnormal sensitivity of the loop of Henle to calcium and magnesium ions. By contrast, the hypermagnesemia that occurs in chronic renal failure results from the reduced glomerular filtration of magnesium.
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PMID:Abnormal renal magnesium handling. 826 9

To investigate interactions between sex hormones, dietary fructose, and a severe magnesium deficiency on calcium metabolism, 10 week old ovariectomized (OVX) female, and orchiectomized (ORX) males rats were studied. The OVX and ORX animals were divided into two groups: one half of the animals in each group was injected with beta-oestradiol-3-benzoate dissolved in sesame oil twice a week; the other half was injected with testosterone cypionate in sesame oil twice a week. All animals were pari-fed a severely magnesium-deficient fructose diet. After a 4 week experimental period, a 24 h urine sample was collected for measurements of cAMP, calcium, magnesium, and phosphorus. Blood was collected for determination of calcium, magnesium, phosphorus, 25-hydroxy- and 1.25-dihydroxycholecalciferol [25(OH)D, 1.25(OH)2D], and parathyroid hormone (PTH). Femurs were used for measurements of bone mineral content (BMC) and density (BMD). Oestrogen treatment produced hypercalcaemia and hypercalciuria, and, further, this was higher in female than in male rats. In contrast, testosterone treatment produced hypocalcaemia and hypocalciuria. Hypocalcaemia in testosterone-treated animals may stimulate secretion of PTH. Testosterone-treated animals had significantly lower BMD than oestrogen-treated animals. High circulating PTH seemed to cause bone loss in the testosterone group. High PTH may stimulate hydroxylation of 25(OH) D to 1.25(OH)2D in the kidneys, and high circulating 1.25(OH)2D would antagonize bone formation. Either endogenous or exogenous oestrogen increased kidney calcification. The study indicates that oestrogen-fructose-magnesium interaction on calcium metabolism was significantly different from that of testosterone.
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PMID:Exogenous oestrogen affects calcium metabolism differently from exogenous testosterone in ovariectomized or orchiectomized rats fed a high fructose diet severely deficient in magnesium. 881 91

Calcitriol is effective in suppressing PTH levels in haemodialysis patients with hyperparathyroidism but has a low therapeutic index. There is a search for other vitamin D sterols that suppress PTH but cause less hypercalcaemia. We review evidence that 1 alpha-hydroxy-vitamin D2 (1 alpha-D2) may be an effective and safer alternative to calcitriol. In vitamin D-deficient rats, 1 alpha-D2 is equipotent to 1 alpha-D3, which is converted to calcitriol before it acts; but, in normal rats, 1 alpha-D2 is much less toxic at high doses. In osteopenia models, either steroid-induced or following ovariectomy, 1 alpha-D2 is equal to or more effective than 1 alpha-D3 in preventing bone loss but causes less hypercalciuria. Studies in osteoporotic women reveal minimal hypercalciuria with 1 alpha-D2 at doses up to 4 micrograms/day, data suggesting greater safety than reported with calcitriol or 1 alpha-D3. Preliminary data in haemodialysis patients with secondary hyperparathyroidism demonstrate the efficacy of 1 alpha-D2 in suppressing PTH levels with minimal untoward effects on serum Ca and no effects on serum P. Taken together, these observations suggest that 1 alpha-D2 deserves strong consideration as a therapeutic agent for secondary hyperparathyroidism associated with end-stage renal disease.
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PMID:1 alpha-Hydroxy-vitamin D2: a new look at an 'old' compound. 884 Mar 32

The aim of the study was to characterize abnormalities of calcium-phosphate and vitamin D3 metabolism in children with a past history of "mild" Lightwood-type idiopathic infantile hypercalcaemia. Seventeen seemingly healthy children aged 2-12 years, with long-term idiopathic hypercalcaemic syndrome since infancy were studied. Two reference groups were also included (vitamin D3 intoxication/healthy and Williams groups). Despite a long-term milk-restricted diet and a restricted vitamin D3 intake, urinary calcium excretion in the study group was 0.117 +/- 0.07 mumol/kg per 24 h. Compared with the reference groups (0.047 +/- 0.029 and 0.067 +/- 0.06 mumol/kg per 24 h, P < 0.05), there was significant hypercalciuria in the children with idiopathic hypercalcaemia since infancy. Serum concentrations of 25-hydroxyvitamin D3 in the study group were also elevated compared with the reference groups (57.4 +/- 15.5 vs. 34.6 +/- 9.3 and 22.7 +/- 10.5 ng/ml). 1,25-Dihydroxyvitamin D3 levels were at the upper limit of normal (45.9 +/- 13.1 vs. 35.0 +/- 8.1 and 30.0 +/- 13.7 pg/ml). Non-progressive, clinically silent nephrocalcinosis was visible on ultrasound examinations. The disturbances of vitamin D3 and calcium-phosphate metabolism persistent in the normocalcaemic phase of idiopathic infantile hypercalcaemia may be a primary metabolic defect of the condition. The mechanisms leading to elevation of metabolites of 1,25-dihydroxy- and 25-hydroxyvitamin D3 and the relationship between this and persistent hypercalciuria and nephrocalcinosis need pathophysiological explanation.
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PMID:Persistent hypercalciuria and elevated 25-hydroxyvitamin D3 in children with infantile hypercalcaemia. 903 62

Calcitriol has been widely used in the management of osteoporosis, but its efficiency is a matter of controversy. It is not known whether combinations of calcitriol and antiresorptive agents such as etidronate and calcitonin are superior to calcitriol alone in the treatment of postmenopausal osteoporosis. To make this determination, 30 Turkish women with postmenopausal osteoporosis between 45 and 68 years of age were randomized to receive either intermittent cyclical etidronate (400 mg/day, for 14 days) followed by 60 days of cyclical calcitriol therapy 0.25 microg twice daily (group 1; n = 10), or calcitriol 0.25 microg twice daily (group 2; n = 10), or calcitriol 0.25 microg/day in combination with 100 IU intranasal salmon calcitonin taken every other day (group 3; n = 10) through a 1-year period. Bone mineral density (BMD) of lumbar spine (L2 to L4) was determined for each patient by dual-photon absorptiometry (153Gd) at baseline, after 6 months, and at the end of the study. There was no significant difference among groups with respect to mean spinal BMD at baseline, after 6, and after 12 months. No significant spinal BMD changes occurred in any group from baseline, after 6 months, and after 12 months. Four patients in groups 1 and 2 and five patients in group 3 developed hypercalcemia at least once during therapy. Hypercalciuria occurred at least once in 9, 10, and 7 patients in groups 1, 2, and 3, respectively. One patient in group 2 developed a renal stone at the end of the study. Mean urine hydroxyproline levels did not change significantly in any group with respect to baseline. The data suggest that one-year treatment with calcitriol, given either alone or in combination with antiresorptive agents, does not improve spinal BMD in Turkish women with postmenopausal osteoporosis, and is associated with a high rate of adverse events.
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PMID:Comparison of calcitriol treatment with etidronate-calcitriol and calcitonin-calcitriol combinations in Turkish women with postmenopausal osteoporosis: a prospective study. 919 11

Vitamin D is a steroid hormone best known for its activity in regulating calcium and bone metabolism. Epidemiological evidence suggests that vitamin D may play a role in inhibiting the development of colon and prostate cancer. Vitamin D receptors are expressed in many types of malignant cells; in vitro and in vivo vitamin D and vitamin D analogues are active in suppressing the development and inhibiting the growth of numerous human and animal tumors. The major toxicity of the active form of vitamin D, 1,25-dihydroxycholecalciferol (calcitriol), is the induction of hypercalcemia. There are no data indicating the maximum tolerated dose of calcitriol administered every other day (QOD) s.c. We hypothesized that this route and schedule would permit administration of higher doses of calcitriol, which might have anticancer activity. We conducted a Phase I trial of calcitriol given s.c. QOD in patients with advanced solid tumors. Thirty-six patients were entered at doses ranging from 2 to 10 microg QOD; dose-limiting toxicity (hypercalcemia) occurred in three of three patients entered at the 10-microg QOD dose. Hypercalciuria occurred at all dose levels examined. No other toxicity was seen. Assessment of serum calcitriol concentrations by a RIA revealed a decrease in concentration-time curves on day 7 compared to day 1 of therapy. A dose-dependent increase in peak serum level and estimated area under the concentration-time curve was seen. The maximum serum levels occurred at the 10-microg QOD dose: 288 +/- 74 and 321 +/- 36 pg/ml at days 1 and 7, respectively. The normal range of calcitriol serum concentration, determined using this assay, is 16-56 pg/ml. Serum calcitriol levels were maintained at near peak concentrations for at least 8 h following s.c. injection. This study indicates that substantial doses of calcitriol can be administered via this route with tolerable toxicity. Studies to explore approaches to ameliorate the hypercalcemia induced by calcitriol and to explore alternative schedules and interactions with other agents are warranted.
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PMID:A Phase I trial of calcitriol (1,25-dihydroxycholecalciferol) in patients with advanced malignancy. 1038 17

In kidney stone patients, high protein intake and calcitriol overproduction are factors leading to hypercalciuria, but there are conflicting reports on the effects of dietary protein on calcitriol production. To investigate the relationships between serum calcitriol, dietary protein intake, and urinary calcium excretion, 33 male idiopathic calcium stone formers (aged 20-60 years), with normal renal function and on unrestricted diet, have been studied. Dietary protein intake was estimated by the protein catabolic rate determination. Abnormally elevated calcitriol levels were found in 16 patients (48.5%) who had similar levels of serum intact parathyroid hormone and phosphate, creatinine clearance, and calcium and phosphate urinary excretion, but lower protein catabolic rate (82+/-16 vs. 97+/-20 g/day, P<0.05) than the patients with normal calcitriol levels. The calcitriol to intact parathyroid hormone ratio was higher in hypercalciuric than in normocalciuric patients (2.4+/-1.1 vs. 1.6+/-0.8, P<0.05). Calcitriol was positively correlated with plasma calcium (r=0.41, P<0.01) and inversely with protein catabolic rate (r=-0.42, P<0.01). Protein catabolic rate was positively correlated with creatinine clearance (r=0.69, P<0.001) and urinary phosphate excretion (r=0.72, P<0.001). No relationship was observed between calcitriol and creatinine clearance. These results confirm the calcitriol overproduction in calcium stone disease and that the high calcitriol to intact parathyroid hormone ratio is the main feature associated with hypercalciuria. Calcitriol serum levels appear to be unrelated to creatinine clearance, whereas there is an inverse relationship with protein catabolic rate. This suggests that low rather than high dietary protein intake may favor the increase of calcitriol synthesis in male calcium stone formers with normal renal function.
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PMID:Serum calcitriol and dietary protein intake in idiopathic calcium stone patients. 1043 67

Although topical vitamin D3 derivatives have been used in the treatment of patients with psoriasis for the past 15 years, questions remain about the indications and limitations of application. Extensive personal experience gained during the development of calcitriol (1alpha25-dihydroxyvitamin D3) is therefore reviewed. Three double-blind, vehicle-controlled trials have revealed that calcitriol 3 microg g(-1) ointment (Silkis ointment, Galderma Laboratories) has very good clinical efficacy. In a left-right comparison with vehicle ointment, complete clearance of psoriatic lesions was achieved in 48% of sites treated with calcitriol and a further 41% showed considerable or definite improvement. The clinical response to calcitriol in another study was as good as, or even better than, that achieved with betamethasone valerate 0.1% ointment. A preparation containing calcitriol 15 microg g(-1) did not show any clinical superiority to the lower dose but was associated with a higher risk of hypercalciuria, particularly when applied to extensive skin lesions. These results suggest that calcitriol 3 microg g(-1) ointment is an effective and safe treatment for chronic plaque psoriasis.
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PMID:Efficacy and tolerance of topical calcitriol 3 microg g(-1) in psoriasis treatment: a review of our experience in Poland. 1150 7

Hypercalciuria and hyperoxaluria are important risk factors in the pathogenesis of kidney stones. Urinary glycolate has also been reported to be elevated in patients with renal stones. 1,25-Dihydroxyvitamin D(3), the active metabolite of vitamin D, has been reported to induce hyperoxaluria after either oral or intravenous administration. 1-alpha-D(3), a synthetic derivative of vitamin D, together with ethylene glycol, has been reported to induce renal stones in experimental rats. We have examined the effect of 1-alpha-vitamin D(3) on urinary oxalate and glycolate excretion. Our results indicate that 1-alpha-D(3), together with ethylene glycol, caused a significant increase in urinary glycolate, without a parallel rise in urinary oxalate excretion, in ethylene glycol-fed rats. This increase in urinary glycolate was due to the synergistic effect of both drugs.
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PMID:Effect of vitamin D3 on the conversion of ethylene glycol to glycolate and oxalate in ethylene glycol-fed rats. 1263 32

Vitamin D deficiency is not possible to correct with the nutritional vitamin D doses in postmenopausal women with decreased bone mineral density. The aim of study was to evaluated the effectivity and safety of 15,000 IU/week vitamin D administrated in 52 postmenopausal women with osteopenia or osteoporosis. Patients were divided into two groups. Treated group was supplemented by calcium 0.5 g/d and 25-hydroxycholecalciferol 15,000 IU/week and control group was supplemented by calcium and placebo for two months. Plasma calcium concentration did not change in the vitamin D treated group while it decreased (p < 0.001) in the control group. Neither calciuria nor fractional excretion of calcium changed during the treatment period. Plasma inorganic phosphate concentration did not change in any group, but urinary inorganic phosphate excretion increased in the vitamin D treated group (p < 0.001). The starting 25-hydroxycholecalciferol plasma concentrations were almost at the deficiency range in both groups. The 25-hydroxycholecalciferol plasma concentration increased substantially (p < 0.001) in the treated group, but it remained at the starting level in control group during the treatment period. Similar plasma concentration increase (p < 0.001) was apparent also in 1.25-dihydroxycholecalciferol. Plasma intact parathormone concentration did not change in the vitamin D treated patients, while it increased (p < 0.01) in the control group. None of the vitamin D treated women suffered from hypercalcemia and mild hypercalciuria was observed in one patient. In conclusion, the study presents an evidence on the effectiveness and safety of 15,000 IU/week 25-hydroxycholecalciferol dosage schedule.
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PMID:[Intensive vitamin D supplementation in the treatment of osteoporosis]. 1521 94


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