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Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of insulin on plasma and bone mineral homeostasis was studied in the BB rat model, which develops an autoimmune form of diabetes at the age of about 100 days. Untreated diabetes of short duration resulted in hypercalciuria and intestinal calcium malabsorption despite increased free concentrations of serum 1,25-dihydroxyvitamin D. The concentrations of two vitamin D-dependent calcium-binding proteins were also decreased: a low duodenal calbindin-D 9K concentration corresponding to the low intestinal active calcium absorption and a low serum osteocalcin concentration, corresponding to a low bone formation and highly correlated with serum IGF-I concentration. Indeed, on bone histology a very low number of osteoblasts and low osteoblast activity (osteoid formation and mineral apposition rate) were observed. Similar abnormalities persisted in rats with long-standing diabetes resulting in markedly decreased bone mass and increased brittleness of bone. Diabetes therefore resulted in low-turnover osteoporosis. Several hormones (testosterone, growth hormone and 1,25-dihydroxyvitamin D) and growth factors (IGF-I and its binding proteins) with known effects on bone were markedly decreased in diabetic rats. A continuous infusion of testosterone, GH or 1,25-(OH)2D3 for 14 d by miniosmotic pumps could not improve the biochemical or histomorphometric abnormalities. Insulin infusion for 2 weeks, however, rapidly increased and overcorrected the number of osteoblasts, normalized serum osteocalcin and IGF-I concentrations but could not yet normalize bone mineralization. Continuous infusion of IGF-I alone did not improve the osteoblast number of osteocalcin but markedly stimulated bone mineralization. From these data we can conclude that both insulin and IGF-I are potent bone growth factors but with different mode of action. In human type 1 diabetes, a similar decrease in serum osteocalcin and IGF-I was observed. A reduction of regional bone mass, both in long and trabecular bones, is frequently observed in human diabetes. Cumulative data from case control studies indicate that the life-time fracture risk is increased in diabetes.
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PMID:Diabetic bone disease. Low turnover osteoporosis related to decreased IGF-I production. 146 60

This study aimed to evaluate whether recombinant human growth hormone (rhGH) or insulin-like growth factor-I (rhIGF-I) can reverse or prevent further bone loss in aged osteopenic ovariectomized (OVX) rats and to compare their effects with those of 17 beta-estradiol (E2). Twelve-month-old rats were OVX, remained untreated for 8 weeks, and subsequently received daily subcutaneous (SC) injections of rhGH (75 micrograms/day), rhIGF-I (250 micrograms/day), E2 (1.5 micrograms/day), and their respective combinations during 8 weeks, and were then compared with sham-operated, pretreatment OVX, and saline-treated OVX rats. A single sc injection of rhGH resulted in peak hGH concentrations after 90 minutes, with a half-life of 124 minutes; the highest plasma IGF-I concentrations were reached 45 minutes after rhIGF-I injection (+57% vs. baseline) with a gradual decline thereafter. Measurements included: biochemical parameters of bone remodeling (plasma osteocalcin and urinary pyridinolines); histomorphometry of proximal tibial metaphysis; DXA of femur; biomechanical analysis of femur and fifth lumbar vertebra (L5); plasma 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), and calbindin-D9K in duodenal mucosa. Whereas all E2-treated OVX rats had much suppressed bone remodeling, rhGH or rhIGF-I had no effect on any biochemical or histomorphometrical parameter of remodeling. The bone mineral density (BMD) at the distal femoral metaphysis as well as parameters of strength at L5 were maintained at pretreatment values in OVX rats treated with E2, GH, or IGF-I, but not in saline-treated OVX rats; their effects were not additive, however. Trabecular bone volume in the tibial metaphysis was also higher in rats treated with these agents than in saline-treated rats, but this was more apparent at the primary than at the secondary spongiosa, suggesting that their mechanism of action is on primary spongiosa formation or breakdown. E2 alone was ineffective to augment the BMD at the femoral diaphysis; however, the diaphyseal BMD was 12-14% higher (p < 0.01) after 8 weeks of GH treatment than in pretreatment or saline-treated OVX rats and sham-operated rats, while IGF-I was less effective than GH, GH or IGF-I treatment had no effect on plasma 1,25(OH)2D3 or duodenal calbindin-D9K concentrations, but the combination of GH or IGF-I with E2 potentiated the effect of E2 to stimulate calbindin-D9K concentrations and urinary calcium excretion, indicating "hyperabsorption hypercalciuria." In conclusion, the administration of rhGH and rhIGF-I, like that of E2, into aged OVX rats prevents further loss of bone mass and strength at sites containing trabecular bone. In addition, rhGH increases cortical bone mass above pretreatment values.
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PMID:Effects of recombinant human growth hormone and insulin-like growth factor-I, with or without 17 beta-estradiol, on bone and mineral homeostasis of aged ovariectomized rats. 891 80

Growth retardation is a cardinal feature of children with renal tubular acidosis. This is reversible by correcting the non-uremic acidosis with alkali therapy. Sodium bicarbonate solutions or citrate solutions have been used for this purpose. However, the odious taste of these medications almost invariably causes medical noncompliance. The persistent and often profound metabolic acidosis from medical noncompliance, precipitates hypercalciuria and hypocitraturia, and increases the risk of nephrocalcinosis. The mechanism of the growth retardation in renal tubular acidosis is thought to be related to a blunting of anterior pituitary growth hormone secretion. In experimental metabolic acidosis, the growth hormone secretory pulse areas are reduced. Just as importantly, hepatic growth hormone receptor expression and IGF-I mRNA were blunted in metabolic acidosis. In uremia, growth retardation is secondary to a host of factors including metabolic acidosis, renal osteodystrophy, and the side effects of treatment such as corticosteroids, which compound the growth retardation. Growth hormone secretion by individual pituitary cells was stimulated by corticosteroids but, paradoxically, the total number of somatotropes was suppressed. In uremia, the secretion of growth hormone was not different from controls at any level of growth-hormone-releasing hormone challenges. Hepatic IGF-I mRNA was markedly reduced in uremic rats. Growth hormone receptor expression was significantly reduced in uremic acidotic rats. The growth hormone and IGF-I expression on the growth plate of the long bone of uremic rats was reduced. IGF-I immunoreactivity was present in both the hypertrophic and proliferative zones. The lack of growth of the proliferative zones suggested growth hormone and IGF-I resistance in uremic chondrocytes.
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PMID:Growth hormone and insulin-like growth factor in non-uremic acidosis and uremic acidosis. 906 56

Reduced bone formation has been documented in both children and adults following burn injury of > or = 40% total body surface area. In children, reduced bone formation and hypercalciuria may be the underlying causes of acute and sustained reduction in bone mineral density. The possible consequences of this reduction are an increase in extrapolated annual fracture incidence and reduced peak bone mass. Excessive endogenous glucocorticoid production, immobilization, bone marrow suppression, and magnesium depletion are all postulated as underlying causes. The most promising potential management agent is recombinant human growth hormone, which can stimulate bone formation via production of insulin-like growth factor I(IGF-I) and its associated binding protein, IGFBP-3, which correlates with bone mineral density in adults. Long-term treatment may be necessary to see a positive effect on bone formation and bone density. Correcting any detected magnesium depletion, and exercise as tolerated, are two other management strategies that might improve bone formation in this population.
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PMID:The management of acute bone loss in severe catabolism due to burn injury. 943 50

Hypercalciuria is a common side effect during total parenteral nutrition (TPN). We report a patient with long-term TPN, who demonstrated hypercalciuria, hypercalcemia and growth retardation. The patient is a six-year-old Japanese girl with Hirschsprung disease (jejunal agangliosis). Jejunostomy was performed at one-month old and since then her nutrition has depended mostly on TPN. When she was 3 years old, continuous TPN was switched to cyclic TPN (on TPN for 11 hrs and off TPN for 13 hrs). The urinary calcium level has been elevated (Ca/Cre ratio, 1.0) since 3 months of age, whereas serum calcium levels stayed within normal range for a while. The serum calcium levels started to elevate to 12 to approximately 13 mg/dl when she was 3 years and 8 months old. She showed growth retardation (height SD score was -4.2SD when she was 5 years and 8 months old) and deteriorated renal tubular function with renal glycosuria, elevated beta 2-microglobulin (beta2-MG) and N-acetyl-beta-D-glucosaminidase. She was referred to our division for the investigation and treatment of growth disturbance and Ca metabolism. Her bone age was delayed (BA/CA 0.62) and serum IGF-I level was decreased but her GH response to provocation test was normal. Bilateral nephrocalcinosis was revealed by renal echogram and CT scan. By reducing calcium content in TPN solution, the serum and urinary calcium levels could be maintained within normal range and her renal function and growth velocity was improved.
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PMID:Growth and metabolic disturbances in a patient with total parenteral nutrition: a case of hypercalciuric hypercalcemia. 1089 Feb 3