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)

Most women with Turner syndrome (TS) have no gonadal activity and thus lack estrogen. Bone mineral density (BMD) is often reduced, leading to an increased risk of osteoporosis and fractures. However, growth retardation with reduced final height and other endocrine disturbances may compromise interpretation of skeletal measurements. The aim of the present study was to explore skeletal findings, bone metabolism, and calcium homeostasis in TS. Sixty women with TS (age, 37 +/- 9 yr) and 181 normal age-matched female controls were studied. Bone area (A; square centimeters), bone mineral content (BMC; grams), area-adjusted BMD (aBMD; grams/square centimeter), and volumetric BMD (vBMD; grams/cubic centimeter) were measured at lumbar spine, femoral neck, and forearm using dual energy x-ray absorptiometry. Twenty-eight percent had osteopenia, and 23% had osteoporosis, according to World Health Organization criteria. At the lumbar spine, A, BMC, aBMD, and vBMD were reduced by 18, 27, 11, and 6%, respectively; at the femoral neck, A, BMC, and aBMD were reduced by 2, 10, and 8%, respectively, whereas the 9% reduction in vBMD was insignificant (P = 0.07); and in the forearm, A, BMC, and aBMD were reduced by 53, 55, and 9%, respectively. Bone markers indicated an enhanced bone resorption (21 and 23% increase in C-terminal and N-terminal cross-linking telopeptides of type I collagen/creatinine, respectively) with unchanged (osteocalcin, procollagen I N-terminal propeptide) or reduced (54% reduction in bone alkaline phosphatase) bone formation. Plasma levels of calcium and 25-hydroxyvitamin D (26%) were reduced, and PTH levels increased (74%) in TS. IGF-I (30%), IGF binding protein 3 (18%), testosterone (50%), and SHBG (40%) were reduced in TS. In summary, A, BMC, and aBMD were found to be universally reduced in TS, whereas vBMD was slightly reduced in the spine. Increased resorption of bone was present, with normal or blunted bone formation, suggesting uncoupling or imbalance in bone remodeling. Skeletal changes may be induced by chromosome abnormalities or by secondary endocrine or metabolic changes related to a relative estrogen deficiency, testosterone deficiency, reduced IGF-I, low vitamin D status, and secondary hyperparathyroidism.
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PMID:Marked disproportionality in bone size and mineral, and distinct abnormalities in bone markers and calcitropic hormones in adult turner syndrome: a cross-sectional study. 1205 Feb 53

Hip fracture is one of the severest consequences of osteoporosis affecting elderly women, but abnormalities of bone turnover responsible for bone loss have not been clearly defined. This study evaluated the relationship of bone turnover parameters to hip fracture in postmenopausal elderly women. We also investigated the effects of endogenous hormones and vitamin D deficiency on osteoporotic hip fracture. The subjects were 21 osteoporotic patients with hip fracture (study group) and 20 healthy postmenopausal women (control group). We measured osteocalcin levels, total and bone alkaline phosphatase (T-ALP and B-ALP), calcitonin, intact parathyroid hormone (iPTH), serum 25 hydroxyvitamin D (25OHD), urinary free deoxypyridinoline (D-pyr) and cross-linked N-telopeptides of type 1 collagen (NTx) levels. Serum T-ALP and B-ALP levels in the study group were lower than those of the control group. The mean serum 25OHD levels in the study group were not significantly different from the control group, but in five cases the mean serum iPTH level was increased. The mean urinary NTx levels were significantly increased in the study group compared with the control group (p<0.05). There was no significant increase in urinary free D-pyr between the two groups. There was significant correlation between serum T-ALP levels and B-ALP levels and between serum iPTH levels and B-ALP levels. The mean serum SHBG level in the study group was higher than in the control group (p<0.05). These data suggest that postmenopausal hip fracture patients have biochemical evidence of decreased bone formation and increased bone resorption compared with postmenopausal healthy subjects. We suggest these abnormalities play a role in the decrease of bone mass and the consequent increase in bone fragility that characterises osteoporotic hip fracture.
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PMID:Relationship of bone turnover parameters, endogenous hormones and vit D deficiency to hip fracture in elderly postmenopausal women. 1213 39

To examine the effect of estradiol (E(2)) without the confounding effect of hypothalamic-pituitary feedback, we studied men with prostate cancer in whom gonadotropin secretion was suppressed by LH-releasing hormone agonists (LHRH-A). Fourteen men over 65 yr of age and receiving established LHRH-A treatment (EST group) without bony metastases and 12 men who received LHRH-A as neoadjuvant therapy for locally advanced prostate cancer (NEO group) were randomized (double blind) to receive either 1 mg/d micronized E(2) (n = 12) or placebo (PL; n = 13) for 9 wk. E(2), estrone, testosterone, SHBG, PTH, and 25-hydroxy- and 1,25-dihydroxyvitamin D levels as well as markers of bone resorption [N- and C-telopeptide cross-links (NTX and CTX) and deoxypyridinoline] and bone formation (bone-specific alkaline phosphatase, osteocalcin, and N-terminal type I collagen) were measured before LHRH-A in the NEO group, before [baseline (BL)] and after 9 wk of E(2) or PL in all patients, and 6 wk after E(2) treatment in the EST group. In the NEO group, hormone levels fell 3 wk after the initial LHRH-A injection, and deoxypyridinoline increased significantly (P = 0.006). At BL, the EST group had higher bone turnover due to the longer duration of LHRH-A treatment. With E(2) treatment, E(2) levels rose into the normal male range, and two resorption markers decreased significantly from BL by 33% for NTX (P < 0.001) and 28% for CTX (P = 0.009). Bone formation markers did not change. PTH increased by 43% from BL (P < 0.01) in the E(2) group and decreased 16% from BL in the PL group (P < 0.01). Ionized calcium did not change in the E(2) group, but increased in the PL group by 2.3% (P < 0.01). NTX and CTX increased 6 wk after E(2) withdrawal in the EST group. We conclude that E(2) inhibits bone resorption in hypogonadal men through a direct skeletal effect that is independent of PTH. Low dose estrogen may be an option for the prevention and/or treatment of bone loss in this population.
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PMID:The effect of micronized estradiol on bone turnover and calciotropic hormones in older men receiving hormonal suppression therapy for prostate cancer. 1241 49

The purpose of this study was to prospectively evaluate the impact of smoking cessation on hormonal concentrations, sex hormone-binding globulin (SHBG) and markers of bone turnover in postmenopausal women. Sixty-six women who were either users or non-users of estrogen replacement therapy (ERT) were randomly assigned, using a weighted randomization scheme, to smoking cessation (SC) or to smoking cessation after 6 weeks of monitoring (wait-list control group, WLC). We measured hormones [estrone, estradiol, testosterone, parathyroid hormone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS) and androstenedione] and SHBG, markers of bone turnover [procollagen peptide (PINP), bone alkaline phosphatase (BAP), and osteocalcin (OC), N- and C-terminal collagen cross-links (NTx and CTx)], and cotinine, at baseline and again at 6 weeks in women who reported smoking cessation and in women randomized to the WLC group. Analyses included 20 subjects who quit or significantly reduced their smoking and 18 subjects in the WLC group. After controlling for differences in age and ERT use between groups, we found a significant change in SHBG in the SC vs. the WLC group (-8% vs. +5%, respectively; p = 0.01), and in DHEA (-18% vs. -5%, respectively; p = 0.04), but not in other hormonal concentrations. We also noted a significant change in NTx in the SC vs. WLC group (-5% vs. +56%, respectively, p = 0.01), but not in other markers of bone turnover. Percentage changes in SHBG and NTx were correlated with changes in plasma cotinine (r = 0.48; p = 0.004 and r = 0.36; p = 0.04, respectively). Six weeks of smoking abstinence produces reductions in SHBG and NTx. This may partly explain how smoking contributes to osteoporosis in postmenopausal women.
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PMID:Effects of smoking cessation or reduction on hormone profiles and bone turnover in postmenopausal women. 1252 4

Male osteoporosis is an increasingly important health problem. It is known that sex steroid hormones play an important role in regulating bone turnover and bone mass in males as well as in females. However, the exact mechanism of bone loss in men remains unknown. In the present study, 200 elderly men (age range, 55-85 yr) were followed for 4 yr to evaluate the relationships between hormone levels, bone turnover markers, bone mineral density, and rates of bone loss. Femoral and lumbar bone mineral density, bone ultrasound parameters at the os calcis, serum testosterone (T), serum estradiol (E(2)), SHBG levels, and bone turnover markers (urinary crosslaps and bone alkaline phosphatase) were evaluated for each man at enrollment and 4 yr afterward. The free androgen index (FAI) and free estrogen index (FEI) as well as measures of the bioavailable sex hormones [calculated bioavailable E(2) (c-bioE(2)) and T (c-bioT)] were calculated from total hormone levels and SHBG. In the total population, T, c-bioT, c-bioE(2), FAI, and FEI, but not E(2), decreased significantly with age, whereas SHBG increased significantly. Subjects with FEI, c-bioE(2), and E(2) levels below the median showed higher rates of bone loss at the lumbar spine and the femoral neck as well as higher speed-of-sounds decrease at the calcaneus with respect to men with FEI, c-bioE(2), and E(2) levels above the median. Serum bone alkaline phosphatase and urinary crosslaps were significantly higher in men with FEI, c-bioE(2), and E(2) in the lower quartile than in men with FEI, c-bioE(2), and E(2) levels in the higher quartile. No statistically significant differences were observed in relation to T, c-bioT, or FAI levels. Finally, the ratio between E(2) and T, an indirect measure for aromatase activity, increased significantly with age and was higher in normal than in osteoporotic subjects. In conclusion, results from the present study indicate an important role of estrogens, and particularly of the ability to aromatize T to E(2), in the regulation of bone loss and bone metabolism in elderly men.
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PMID:Longitudinal association between sex hormone levels, bone loss, and bone turnover in elderly men. 1460 69

The role of estrogen deficiency in male osteoporosis is still under discussion. One hundred five subjects, 65 of them suffering from osteoporosis (mean age, 53.9 years) and 40 age-matched controls were studied. Osteoporosis was defined by a T score < -2.5 in the lumbar spine or at the femoral neck. Forty-one (63.1%) of the subjects had a history of low-energy fractures, involving vertebrae in 33 cases (50.8%). Osteoporosis was considered to be idiopathic in 33 subjects (50.8%) for whom no etiology could be found. We measured levels of total estradiol (pg/ml, with a detection threshold of 4 pg/ml), total testosterone (ng/ml), and their carrier protein, that is, sex hormone-binding globulin (SHBG, pmol/ml). Various markers of bone remodeling were also measured. Two of them provide an estimate of bone formation-osteocalcin (OC) and bone alkaline phosphatase (BAP). Two others evaluate bone resorption-procollagen type I C-terminal telopeptide (ICTP) and serum C-telopeptide of type I collagen (sCTX). There was no significant difference in estradiol levels between controls and osteroporosis patients. We did not find any significant correlation between estradiol levels and spinal bone mineral density (BMD) (r = 0.15, P > 0.05), and the relationship between estradiol levels and BMD at the femoral neck was weak (r = 0.25, P < 0.05). On the other hand, SHBG was significantly higher in the osteoporotic patients than in controls (P < 0.01). This difference persisted after adjustment for body mass index (BMI) and after exclusion of patients with a condition known to increase SHBG levels. Moreover, this carrier protein was negatively correlated with BMD at the femoral neck (r = -0.37, P < 0.01) and at the lumbar spine (r = -0.27, P < 0.05). SHBG also correlates strongly with sCTX (r = 0.37, P < 0.01). Finally, logistic regression analysis showed that serum SHBG concentration was significantly associated with the presence of fractures; the odds ratio of having a fracture was 2.04 [95% confidence interval (CI) 1.2-3.4, P < 0.01] for each increase of 1 standard deviation (SD) in the patient's SHBG level. The stronger relationship was nearly the same for the whole group and for patients with idiopathic osteoporosis. This study therefore suggests that SHBG may play a key role in male patients with idiopathic or secondary osteoporosis. It shows that serum SHBG concentration is increased in middle-aged men with osteoporosis and is correlated with hip, spine BMD, and sCTX levels. Finally, our findings are in agreement with previous studies which suggest that serum SHBG is a new biological marker of fracture risk in men.
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PMID:Sex hormone-binding globulin, estradiol, and bone turnover markers in male osteoporosis. 1519 39

The clinical study of treated subjects and nontreated controls was made in healthy eumenorrheic young postadolescent women volunteers in the Department of Obstetrics and Gynaecology at Cagliari University, to investigate whether an oral contraceptive (OC) containing drospirenone (3 mg) plus ethinyl estradiol (30 microg) (DRSP+EE) can affect bone metabolism. Control group (n = 26) and OC group (n = 28) women did not differ in age, body mass index, waist-to-hip ratio and main outcome measures [urinary levels of deoxypyridinoline and pyridinoline, serum levels of osteocalcin, bone specific alkaline phosphatase (bSAP), total testosterone (total-T), sex hormone-binding globulin (SHBG), progesterone and bone mineral density (BMD) at the heel]. The control group was studied at the luteal phase (LP) during both the first and the sixth menstrual cycle; the OC group was studied during the first cycle at the LP, and on days 16-18 of the sixth cycle of DRSP+EE treatment. At the sixth cycle, in the control group, the main outcome measures did not change compared to baseline. In the OC group, deoxypyridinoline, pyridinoline, osteocalcin, bSAP, total-T and progesterone levels were reduced, whereas SHBG levels were increased. The BMD was unchanged compared to baseline. The results suggest that 6-month DRSP+EE treatment decreases bone turnover.
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PMID:Short-term variations in bone remodeling markers of an oral contraception formulation containing 3 mg of drospirenone plus 30 microg of ethinyl estradiol: observational study in young postadolescent women. 1545 33

Multiple factors can contribute to the development of osteodystrophy in patients with chronic liver disease (CLD). Recently, two new cytokines, osteoprotegerin (OPG) and the receptor activator of nuclear factor-kB ligand (RANKL), have been implicated in the pathogenesis of postmenopausal osteoporosis and other metabolic bone diseases. Therefore, the aim of our study was to evaluate bone metabolism, bone mineral density (BMD) and OPG/RANKL system in 65 male patients with CLD and in 65 healthy controls. Our patients showed lower BMD values than controls both at lumbar and femoral levels. Moreover, they had an unbalanced bone turnover with an increased resorption phase, as shown by high levels of urinary deoxypyridinoline and a decreased formation phase, as shown by the slightly, but significant, low levels of bone-alkaline phosphatase. Patients showed lower plasma levels of free-testosterone than controls and higher - although not significantly so - plasma levels of 17 beta-estradiol. Furthermore, patients with CLD had higher levels of sex hormone-binding globulin and OPG, and lower levels of 25-hydroxyvitamin D (25-HOD) and IGF-I than the control group, while RANKL levels were similar in the two groups. In conclusion, our data do not confirm the hypothesis that the OPG/RANKL system could exert a key role in the pathogenesis of hepatic osteodystrophy, but rather that the observed increase in OPG levels may represent either the result of the inflammatory process per se or a compensation for the observed enhanced bone resorption.
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PMID:Hepatic osteodystrophy: does the osteoprotegerin/receptor activator of nuclear factor-kB ligand system play a role? 1627 62

Patients with pituitary resistance to thyroid hormones (PRTH) exhibit features of hyperthyroidism due to normal sensitivity to thyroid hormones in some of the peripheral tissues. There is a lack of information in the literature on the long-term follow-up and treatment of patients with PRTH. Here, we present long-term (9 years) clinical and biochemical follow-up of a patient with PRTH under the treatment of D-T4 initially (for 1.5 years) followed by TRIAC for 5.5 years. An 11.5 year-old girl was evaluated for goiter, palpitations, heat intolerance, sleep disorders, nervousness and frequent stools for 3 years. Her thyroid function tests were consistent with PRTH. Molecular analysis revealed a heterozygous missense mutation of the TRbeta gene at codon 243 in exon 7 (R243Q) and a silent mutation at codon 245 in the index patient and the mother who was later also diagnosed to have PRTH. The patient was started on D-T4 treatment since she exhibited clinical symptoms of hyperthyroidism. After 1.5 years, D-T4 treatment was switched to TRIAC which lasted 5.5 years. During the long course of both treatments, thyroid hormones, TSH, heart rate, thyroid size, and markers of peripheral thyroid status (SHBG and alkaline phosphatase) were monitored. It was concluded that compared to D-T4, TRIAC treatment is more effective in suppressing TSH and lowering thyroid hormone levels in PRTH. However, both treatments were unable to reduce thyroid size. The effects of treatment on symptomatology were also modest. Spontaneous improvement in symptoms was observed with age.
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PMID:9 years follow-up of a patient with pituitary form of resistance to thyroid hormones (PRTH): comparison of two treatment periods of D-thyroxine and triiodothyroacetic acid (TRIAC). 2002 May 87

Postmenopausal women consistently have higher phosphorus levels than similarly aged men. As it is known that estradiol induces phosphaturia in rodents, we evaluated the cross-sectional association of sex hormones with serum phosphorus in 1346 community-living older men (mean age 76) of which 18% had moderate (stage 3) kidney disease. Using linear regression with serum phosphorus levels as the dependent variable, we found that for each 10 pg/ml higher total estradiol level there was a statistically significant 0.05 mg/dl lower serum phosphorus when adjusted for age, ethnicity, testosterone, sex hormone-binding globulin, calcium, estimated glomerular filtration rate, intact parathyroid hormone, 25(OH) vitamin D, bone mineral density, and alkaline phosphatase. These results were similar in individuals with or without chronic kidney disease. Serum testosterone concentrations were also statistically significantly associated with lower serum phosphorus levels. We confirmed these results in an independent sample of 2555 older men, wherein these associations were not attenuated when adjusted for fibroblast growth factor-23 levels. Hence, our study of community-living older men suggests that estradiol may directly or indirectly induce phosphaturia in humans. The mechanism responsible for the association of testosterone with serum phosphorus remains to be determined.
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PMID:Associations of estradiol and testosterone with serum phosphorus in older men: the Osteoporotic Fractures in Men study. 2053 58


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