Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The short-term effects of corticosteroids (CS) administered intravenously (IV) on biochemical parameters of bone metabolism were followed in infants and children. Forty-nine patients from 2 months to 10 years of age, admitted to Pediatrics Department for bronchiolitis, viral-associated wheezing and croup, were treated with IV hydrocortisone or methylprednisolone (10 or 2 mg/Kg/day, respectively) for 3 days. Blood and fasting urine were collected on admission (day 1), 2 days later (day 3) and 12 days after the end of therapy (day 15). Fifty-one children of similar age and gender without respiratory problems or bone diseases were used as controls. On day 3, suppression of the bone formation markers osteocalcin (OC) (P < 0.001) and total alkaline phosphatase (ALP) (P < 0.05) was observed, but not of the bone resorption markers of hydroxyproline, pyridinoline and calcium excretion (UHyp/UCr, UPYD/UCr and UDPD/UCr, UCa/UCr). Significant decreases were indicated in serum phosphate (Pi) and the maximum renal tubular Pi reabsorption (TmP/GFR) compared to basal (P < 0.001). No significant changes were noticed in the circulating levels of calcium (Ca), parathyroid hormone (iPTH), 25OHD, 24,25(OH)2D, 1,25(OH)2D, the insulin-like growth factor-I (IGF-I) and its binding protein-3 (IGFBP-3). Two weeks after therapy, the increase of OC to higher than basal (P < 0.01) indicated a probable activation of the osteoblasts. Serum Pi and the TmP/GFR index values that had significantly decreased by day 3 returned to pretreatment levels by day 15. When assessing the effects of the CS in relation to age, no changes were detected in the levels of OC and total ALP in the <12-month-old children, but a fall of OC was observed in the >1-year-old group (P < 0.001). In contrast to the OC, the effects on serum and renal tubular reabsorption of phosphate were similar for both groups. In conclusion, short-term IV administered CS led to significant but reversible inhibition of bone formation markers, especially detectable in the >1-year-old children, without affecting the bone resorption ones. The adverse effects on phosphate metabolism were also significant, but temporal and irrespective of age.
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PMID:Biochemical markers of bone metabolism in infants and children under intravenous corticosteroid therapy. 1287 99

The aim of this randomised study was to compare the effects of progestins and aromatase inactivators on bone remodelling markers and the components of insulin-like growth factor in patients with metastatic breast cancer. Within the framework of a large (769 patients), randomised double-blind clinical trial comparing exemestane (EXE) with megestrol acetate (MA), serum 17 beta-estradiol (E2), estrone (E1), estrone sulphate (E1S), bone alkaline phosphatase (BAP), carboxy-terminal cross-linking telopeptide of type I collagen (ICTP) and the components of insulin-like growth factor (IGF) family (IGF-1, IGF-2 and IGFBP-3) were determined in 53 patients (24 randomised to EXE and 29 ramdomised to MA). After eight weeks of treatment, both ICTP and BAP increased (p < 0.01) in the EXE group, but only ICTP in the MA group (p < 0.03). The 8-week suppression of E2 and E1S was more pronounced in the EXE group (to, respectively, 11.2% and 9.9% of baseline values) than in the MA group (33.1% and 29.7%). IGF-1 increased (p < 0.01) in both groups, but more so in the patients treated with MA. Estrogen levels negatively correlated with ICTP in both groups, but were not related to BAP in either. IGF-1 negatively correlated with estrogens in both groups. The results of this study indicate that anti-aromatase therapy is associated with increased osteoclast activity, and suggest the existence of possible differential effects of different hormonal therapies on bone remodelling markers regardless of the estrogen suppression induced by EXE.
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PMID:Bone turnover markers and insulin-like growth factor components in metastatic breast cancer: results from a randomised trial of exemestane vs megestrol acetate. 1292 95

Cross-linking of nonglycosylated biotinylated IGF binding protein (IGFBP)-3 to T-47D cell membranes identifies complexes with Mr of 32, 50, 70, and 100 kDa. Nonbiotinylated glycosylated IGFBP-3 competed for binding to each of these sites. The 32-kDa band approximated the size of intact nonglycosylated IGFBP-3, but its abundance was enhanced by cross-linking, and it had a more acidic isoelectric point on isoelectric focusing, suggesting that it had undergone phosphorylation. Immobilized IGFBP-3 was phosphorylated in the presence of (32)P-gamma ATP by both T-47D cell membranes and by intact cells treated with phenylarsine oxide to inhibit internalization. MCF-7 and COS-1 cells were also able to bind and phosphorylated IGFBP-3. IGF-I inhibited both IGFBP-3 binding to membranes and phosphorylation. However, incubation of T-47D cells with IGFBP-3 enhanced binding of (125)I-IGF-I to the cell monolayer indicating that membrane bound IGFBP-3 was able to bind IGF-I. Immobilized IGFBP-3 when phosphorylated by T-47D membranes bound significantly more (125)I-IGF-I than nonphosphorylated IGFBP-3. Treatment with alkaline phosphatase significantly reduced (125)I-IGF-I binding to phosphorylated immobilized IGFBP-3 and also reduced (125)I-IGF-I to T-47D cell monolayers preincubated with IGFBP-3. Phosphorylation of IGFBP-3 by T-47D membranes was partially blocked by inhibitors of both protein kinase A and C. These data demonstrate that binding of IGFBP-3 to breast cancer membranes is accompanied by phosphorylation at the plasma membrane and that both processes are inhibited by IGF-I. However, once phosphorylated the ability of IGFBP-3 to bind IGF-I is enhanced, resulting in increased association of the IGF-I with the cell membrane.
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PMID:Phosphorylation of insulin-like growth factor (IGF) binding protein-3 by breast cancer cell membranes enhances IGF-I binding. 1293 78

Osteoprotegerin (OPG), a natural decoy receptor for osteoclast differentiation factor, is produced by osteoblasts in response to PTH. OPG and its ligand RANKL constitute a complex mediator system involved in the regulation of bone resorption, probably playing an important role in the homeostasis of bone turnover. At present, little is known about the effects of OPG on uremic bone. Successful kidney transplantation reverses many abnormalities of bone metabolism; however, the improvement is often incomplete. The aim of the study was to assess OPG and RANKL concentrations in long-term kidney allograft recipients and their correlations with biochemical markers of bone resorption and formation. The present studies on 48 kidney transplant recipients and 25 healthy volunteers included concentrations of parathormone, osteocalcin, bone-specific alkaline phosphatase, serum CrossLaps, calcidiol, calcitriol, ICTP, PICP, tartrate-resistant acid phosphatase, beta2 microglobulin, IGF-1, IFGBP-1, IGFBP-3, OPG, and RANKL using commercially available kits for measurements. Among kidney transplant recipients OPG and RANKL did not differ between transplant patients and healthy volunteers, whereas other markers of bone formation and resorption were significantly higher in the former group. OPD was related to age, time on dialysis prior transplantation, urea, platelet count, CSA dose, azathioprine dose, 25(OH)D(3), TRAP, IGF-1, IGFBP-3, whereas RANKL was related to leukocyte count, CSA concentration and dose, urine DPD, and beta2 microglobulin content. In healthy volunteers OPG correlated only with CrossLaps, whereas RANKL correlated only with osteocalcin and TRAP. Correlations between OPG, IGF system components, and some markers of bone metabolism may indicate the role of OPG/RANKL system in the pathogenesis of bone metabolism disturbances following renal transplantation.
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PMID:Osteoprotegerin and its correlations with new markers of bone formation and bone resorption in kidney transplant recipients. 1452 97

This longitudinal study evaluated the effects of a triathlon season on bone metabolism and hormonal status. Seven male competitive triathletes (mean age 19.3 years, range 18 - 20) with 5.0 +/- 0.3 years of competition experience were tested twice during the season: at the beginning of training and 32 weeks later. Total and regional bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry, while bone turnover was evaluated by specific biochemical markers: bone-specific alkaline phosphatase (B-ALP), osteocalcin, and urinary type I collagen C-telopeptide. In addition, sexual, calciotropic and somatotropic hormones were also analyzed. After 32 weeks, a BMD increase was found at the lumbar spine (1.9 %; p = 0.031) and skull (3.1 %; p = 0.048), while no variation was observed for total body or at the proximal femur. The B-ALP level decreased (-23.2 %; p = 0.031), but no variation was found for the other bone markers. 1.25 (OH) (2)D3, IGF-1 and the bioavailability IGF-1 index (IGF-1/IGFBP-3) increased by 18.3 % (p = 0.047), 29 % (p = 0.048), 33 % (p = 0.011), respectively, while PTH, testosterone, IGFBP-3 and cortisol concentrations were unchanged. In conclusion, the triathlon season had a moderately favourable effect on BMD, although a slowing down of bone formation activity was observed. No variation in hormonal levels was observed that could have limited the effects of exercise on bone tissue.
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PMID:Competitive season of triathlon does not alter bone metabolism and bone mineral status in male triathletes. 1508 49

As IGF-1 is the major factor that affects bone growth, and both osteocalcin and bone-specific alkaline phosphatase are important markers of bone formation during puberty, there must be a relationship between these markers that does not change according to sex. The aim of this study was to investigate the relationships between pubertal development, the IGF-1 axis, and bone formation in healthy adolescents. Two hundred and five healthy children and adolescents were included in this cross-sectional study. Tanner's classification was used to determine the pubertal developmental stage. Serum IGF-1 levels and IGF-1/IGFBP-3 ratios increased with advancing pubertal stages, and maximum mean values were found at stages III-IV in girls and at stage IV in boys. Serum IGF-1 and IGFBP-3 levels were significantly correlated with osteocalcin and bone-specific alkaline phosphatase levels in boys, but not in girls. This difference between the sexes, and the relation of the IGF-1 axis to increased bone formation during puberty in both sexes, can be explained by the rate of increase of the IGF-1/IGFBP-3 ratio. We conclude that the timing of the increased bone formation rate during puberty; that is, the timing of the pubertal growth spurt, is determined by the maximum increase rate of the IGF-1/IGFBP-3 ratio. But this new hypothesis needs to be supported by longitudinal studies.
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PMID:The relationships between pubertal development, IGF-1 axis, and bone formation in healthy adolescents. 1561 98

Controversy exists about the effect of zinc on growth and the GH-IGF system. Zinc supplementation has been shown to stimulate linear growth in zinc-deficient children. However the mechanism of this effect has not been well characterized. Furthermore, the effect of zinc supplementation on non-zinc-deficient short children is unknown. We investigated the effect of zinc supplementation on endogenous GH secretion, serum IGF-I and IGFBP-3 concentrations, IGF-I and IGFBP-3 generation in response to exogenous GH, bone formation markers, and linear growth of non-zinc-deficient children with idiopathic short stature. We analyzed prospectively serum zinc, IGF-I, IGFBP-3, alkaline phosphatase, osteocalcin, and GH response to clonidine test, and performed a somatomedin generation test before and 6 weeks after zinc supplementation in 22 (16 M, 6 F) prepubertal children with idiopathic short stature. Serum IGF-I increased from 67.4+/-70.6 to 98.2+/-77.3 ng/ml (p <0.001), IGFBP-3 from 2326+/-770 to 2758+/-826 ng/ml (p <0.001), alkaline phosphatase from 525+/-136 to 666+/-197 U/l (p <0.0001), and osteocalcin from 16.8+/-10.6 to 25.8+/-12.8 ng/ml (p <0.05) after zinc supplementation despite there being no difference in GH response to clonidine after zinc supplementation (peak GH 11.6+/-6.9 vs 13.4+/-7.8 ng/ml, GH area under the curve during clonidine test 689+/-395 vs 761+/-468, NS). Percent change in IGF-I and IGFBP-3 during the somatomedin generation test was not significantly affected by zinc supplementation (118% vs 136% and 57% vs 44%, respectively). There was no significant correlation between percentage increase in zinc levels and percentage increase in parameters tested. Height SDS or weight SDS did not improve significantly in 17 patients who continued on zinc supplementation for at least 6 months (6-12 months) (-2.59 vs -2.53 SDS and -1.80 vs -1.67 SDS, respectively). Zinc supplementation increased basal IGF-I, IGFBP-3, alkaline phosphatase and osteocalcin without changing GH response to clonidine. Zinc supplementation did not affect sensitivity to exogenous GH as tested by IGF-I and IGFBP-3 generation test. These results suggest a direct stimulatory effect of zinc on serum IGF-IGFBP-3, alkaline phosphatase and osteocalcin. Despite improvements in the above parameters, zinc supplementation to children with idiopathic short stature with normal serum zinc levels did not significantly change height or weight SDS during 6-12 months follow-up.
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PMID:Effect of zinc supplementation on growth hormone secretion, IGF-I, IGFBP-3, somatomedin generation, alkaline phosphatase, osteocalcin and growth in prepubertal children with idiopathic short stature. 1567 71

Type 1 diabetes mellitus (T1DM) has been inconsistently associated with low bone mineral density (BMD) and increased fracture risk. 86 consecutive T1DM cases and 140 unrelated age and sex matched healthy nondiabetic controls were included in the study. After history and examination, BMD and body composition were assessed by dual energy X-ray absorptiometry (DXA). Serum samples were analyzed for calcium, phosphorus, albumin, creatinine, alkaline phosphatase, 25 (OH) vitamin D3, intact parathormone (PTH) levels (both cases and controls) and HbA1c, antimicrosomal and IgA tissue transglutaminase (IgA TTG) antibodies, cortisol, follicle stimulating hormone (FSH), testosterone, sex hormone binding globulin (SHBG), tetraiodothyronine (T4), thyroid stimulating hormone (TSH), growth hormone (GH), insulin-like growth factor-1 (IGF-1), and insulin-like growth factor binding protein 3 (IGFBP3) (cases only). T1DM cases had a lower BMD as compared to controls at both total body (TB) and lumbar spine (LS) (P < 0.05). Patients with celiac autoimmunity (CA) had significantly, lower BMD as compared to age, sex, and body mass index (BMI) matched T1DM controls. Linear regression analysis showed that low BMD in T1DM patients was associated with poor glycaemic control, lower IGF-1 levels, less physical activity (in total population as well as in male and female subgroups), and lower body fat percentage (in females) and higher alkaline phosphatase level (in males) (P < 0.05).
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PMID:A study of bone mineral density and its determinants in type 1 diabetes mellitus. 2360 45

Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) is a secreted glycoprotein that reduces the bioavailability of IGFs. This glycoprotein has both IGF-dependent and -independent effects on cell growth. However, the mechanisms responsible for the IGF-independent actions of IGFBP-3 are not fully understood. In the present study, we used multiple methodologies including glutathione S-transferase pull-down assay and co-immunoprecipitation to demonstrate that IGFBP-3 can directly interact with vitamin D receptor (VDR) in vitro and in vivo. Furthermore, immunofluorescence co-localization studies showed that IGFBP-3 and VDR could co-localize in the cell nucleus. Reporter gene experiment showed that IGFBP-3 negatively regulates the growth hormone promoter activity induced by ligand-activated VDR. Moreover, real-time RT-PCR demonstrated that IGFBP-3 can inhibit the osteocalcin and CYP24a1 mRNA transcription induced by 1,25-(OH)2D3 in osteoblastic cells. Finally, alkaline phosphatase activity significantly decreased in osteoblastic cells when the cells were transfected with IGFBP-3 in the presence of 1,25-(OH)2D3. In conclusion, these studies provide evidence that overexpression of IGFBP-3 suppresses osteoblastic differentiation regulated by VDR in the presence of 1,25-(OH)2D3. These findings reveal a novel mechanism by which IGFBP-3 functions.
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PMID:Insulin-like growth factor binding protein-3 modulates osteoblast differentiation via interaction with vitamin D receptor. 2377 Mar 68

This study was carried out to investigate the effects of the Achyrantes japonica (A. japonica) extract on serum level of hormones from osteoporosis induced ovariectomized rats. Two month-old rats were ovariectomized (OVX), remained untreated for 8 weeks, and were subsequently administered A. japonica (300 mg/kg) every day for 8 weeks. We examined the effects of treated A. japonica every 10 days on ovariectomy-related changes in Insulin-like Growth Factors (IGF), Insulin-like Growth Factor binding protein-3 (IGBF-3), Estrogen, Calcium, and Phosporus. After 8 weeks, the serum levels of IGF-I, -II, and IGFBP-3 were higher presented as compared to the other two groups (P< 0.05), in the A. japonica extract treatment on OVX rats. Bone alkaline phosphatase levels were increased through A. japonica extract treatment in OVX rats compared to the other two groups. There were no differences between OVX and A. japonica extract treated OVX rats in serum levels of estrogen, but estrogen levels for the sham group were higher than for the other two groups. A. japonica extract is increased to serum levels of IGFs and IGFBP-3 of osteoporosis induced by ovariectomized rats. Thus, the results reveal that the A. japonica extract is a possible role for improvement of osteoporosis induced-ovariectomized rats and has a great potential as an alternative tool for the treatment of osteoporosis.
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PMID:Osteoprotective effect of extract from Achyranthes japonica in ovariectomized rats. 2561 Aug 22


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