Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D00919 (CTX)
 5,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The first weeks of lactation in dairy cows are characterised by elevated bone resorption. The connection between lactation and bone metabolism is still much discussed. In this work, changes in the concentration of plasma parathyroid hormone-related peptide (PTHrP) and markers of bone metabolism were studied in Holstein cows and heifers in the dry period and early lactation to determine the role of PTHrP in the relationship between the rate of bone remodelling and the onset of lactation in dairy cows. Blood samples were taken 14 days before calving ('D-14', n = 23) and then on day 10 ('D+10', n = 21) and day 30 after calving ('D+30', n = 23). Using enzyme immunoassay (EIA), the concentrations of PTHrP, parathyroid hormone (PTH), carboxyterminal cross-linked telopeptide of type I collagen (CTX) and oestradiol and the activity of bone specific alkaline phosphatase (BSALP) were determined. The results showed a statistically significant increase in plasma PTHrP (p < 0.005) and CTX (p < 0.0001) in cows on 'D+10' as compared to 'D-14' and CTX on 'D+30' as compared to 'D-14' (p < 0.0001). Significant negative correlations were found between the concentrations of PTHrP and oestradiol (r = -0.29, p < 0.05) and those of CTX and oestradiol (r = -0.54, p < 0.0001). In nonpregnant heifers (n = 6), the concentration of CTX and the activity of BSALP were significantly higher (p < 0.0001) than in dry cows. The observed increments of PTHrP and bone resorption after parturition reveal adaptations of bone metabolism to lactation in dairy cows.
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PMID:Plasma parathyroid hormone-related peptide and bone metabolism in periparturient dairy cows. 1866 51

Ageing is associated with a gradual bone loss and physical activity has been suggested as practical strategy for a non-pharmacological prevention of osteoporosis. However, until now, the specific mechanism by which physical activity affects bone tissue is not thoroughly understood. The aim of this study was to evaluate the effect of strenuous exercise on bone metabolism as a function of age and fitness level. Eighteen physically highly active elderly participants (mean age 71.7+/-7.3 years, HAcEl group), 18 moderately active elderly participants (mean age 71.9+/-8.6 years, ModEl group) and 9 young physically active participants (mean age 25.8+/-2.3 years, AcYo) participated in this study. Concentrations of plasma ionised calcium (iCa), serum parathyroid hormone (iPTH), 25-hydroxy-vitamin D [25(OH)D], and 1,25-dihydroxy-vitamin D3 [1,25(OH)(2)D3] as well as the bone biochemical markers type-I collagen C-telopeptide (CTX) for bone resorption and osteocalcin (OC) and bone alkaline phosphatase (B-ALP) for bone formation, were analyzed before and after a maximal incremental exercise test. In all groups, iCa decreased significantly (p<0.05 for ModEl and AcYo and p<0.001 for HAcEl) while iPTH increased significantly (p<0.01 for ModEl and HAcEl and p<0.001 for AcYo) after exercise. The levels of 1,25(OH)(2)D3, OC and CTX remained unchanged, while 25(OH)D decreased only in HAcEl group while B-ALP increased in ModEl group. In conclusion, strenuous exercise disturbed calcium homeostasis, mainly the iCa/iPTH equilibrium independently of gender, age or fitness level of the participants while no immediate effect on bone turnover was observed.
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PMID:Response of calciotropic hormones and bone turnover to brisk walking according to age and fitness level. 1876 64

Lithium salts are widely used in treating psychiatric patients. Lithium may be associated with hyperparathyroidism, a risk factor for osteoporosis. However, the data on the effect of lithium on bone mass are conflicting. We assessed bone mineral density with dual-energy X-ray absorptiometry at the hip and lumbar spine in 75 lithium treated outpatients and 75 normal subjects matched for age, sex and body mass index. Serum total calcium, intact parathyroid hormone (PTH), estradiol, osteocalcin, total alkaline phosphatase (ALP) and C-telopeptide (CTX) in addition to fasting urinary calcium excretion were also determined in both groups. The mean (+/-SD) bone density in lithium treated patients was 4.5% higher at the spine (P<0.05), 5.3% higher at the femoral neck (P<0.05) and 7.5% higher at the trochanter (P<0.05). In addition, lithium treated patients had lower serum total ALP (P<0.005), lower serum osteocalcin (P<0.005) and lower serum CTX (P<0.05) but the total calcium, PTH and urinary calcium excretion did not differ significantly between patients and controls. In conclusion, our results suggest that maintenance therapy with lithium carbonate may preserve or enhance bone mass. These data also suggest a lower bone turnover state in those receiving lithium.
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PMID:Lithium's effect on bone mineral density. 1899 57

The aim of this study was to assess the effects of the antiresorptive treatments of alendronate (ALN), risedronate (RIS) and raloxifene (RLX) on the response of bone to endogenous parathyroid hormone (PTH) induced by acute hypocalcemia. Forty women (age, 55-80 years) with postmenopausal osteoporosis (treated with ALN, RIS and RLX or untreated-control group) were given infusions of sodium ethylenediaminetetraacetic acid (EDTA; 10 mg/kg of body weight). Serum ionized calcium (iCa), plasma intact PTH and marker of bone resorption, serum beta C-terminal telopeptide of type I collagen (beta-CTX; beta CrossLaps) were followed for 180 min. In all women, decrease in serum iCa following the EDTA load resulted in an acute increase in serum PTH. Between 60 and 180 min, plasma PTH in the ALN and RIS treated women remained significantly higher than in the control group. The integrated beta-CTX responses (area under curves, AUCs) to peaks of PTH were significantly lower in the ALN treated women than in those treated with RIS, RLX or control group. There was no significant difference in beta-CTX AUC response to PTH between RIS, RLX and control women. Taken together, these findings suggest that in women with postmenopausal osteoporosis treated with ALN, a substantial reduction of bone turnover blunts the acute bone resorbing effect of endogenous PTH.
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PMID:Marked reduction of bone turnover by alendronate attenuates the acute response of bone resorption marker to endogenous parathyroid hormone. 1915 Apr 21

Acceleration of bone remodelling increases the risk of fragility fractures. The objective of the present study was to explore in elderly women whether a vitamin D and Ca-fortified dairy product providing about 17-25 % of the recommended intakes in vitamin D, Ca and proteins would reduce secondary hyperparathyroidism and bone remodelling in a way that may attenuate age-related bone loss in the long term. Thirty-seven institutionalised women, aged 84.8 (sd 8.1) years, with low serum 25-hydroxyvitamin D (5.5 (sd 1.7) ng/ml) were enrolled into a multicentre open trial to consume during 1 month two servings of soft plain cheese made of semi-skimmed milk providing daily 686 kJ (164 kcal), 2.5 microg vitamin D, 302 mg Ca and 14.2 g proteins. The primary endpoint was the change in serum carboxy terminal cross-linked telopeptide of type I collagen (CTX), selected as a marker of bone resorption. Thirty-five subjects remained compliant. Mean serum changes were: 25-hydroyvitamin D, +14.5 % (P = 0.0051); parathyroid hormone (PTH), - 12.3 % (P = 0.0011); CTX, - 7.5 % (P = 0.01); tartrate-resistant acid phosphatase isoform 5b (TRAP 5b), - 9.9 % (P < 0.0001); albumin, +6.2 % (P < 0.0001); insulin-like growth factor-I (IGF-I),+16.9 % (P < 0.0001); osteocalcin, +8.3 % (P = 0.0166); amino-terminal propeptide of type 1 procollagen (P1NP),+19.3 % (P = 0.0031). The present open trial suggests that fortified soft plain cheese consumed by elderly women with vitamin D insufficiency can reduce bone resorption markers by positively influencing Ca and protein economy, as expressed by decreased PTH and increased IGF-I, respectively. The rise in the bone formation marker P1NP could be explained by a protein-mediated increase in IGF-I. Thus, such a dietary intervention might uncouple, at least transiently, bone resorption from bone formation and thereby attenuate age-related bone loss.
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PMID:Inhibition of markers of bone resorption by consumption of vitamin D and calcium-fortified soft plain cheese by institutionalised elderly women. 1951 75

Teriparatide, a parathyroid hormone analogue, is a potent anabolic treatment for postmenopausal osteoporosis. Studies have shown that teriparatide induces large increases in biochemical markers of bone formation after 1 month of therapy followed by a delayed increase in bone resorption markers. The aims of this study were to (1) describe changes in bone turnover markers during 28 days of treatment with teriparatide; (2) identify the earliest time point by which most subjects showed a biochemical response to teriparatide; (3) identify potential biomarkers of positive bone response; (4) describe changes in bone turnover markers 4 weeks after stopping teriparatide. We recruited 15 osteopenic postmenopausal women, ages 55-69 (mean 62) years. All received 20 microg teriparatide subcutaneously for 28 days. Serum levels of the bone formation markers type I collagen N-terminal propeptide (PINP), type I collagen C-terminal propeptide (PICP), osteocalcin (OC), bone alkaline phosphatase (bone ALP), and the bone resorption markers crosslinked C-telopeptide of type I collagen (Sbeta-CTX), crosslinked N-telopeptide of type I collagen (S-NTX) and tartrate-resistant acid phosphatase type 5b (TRACP5b) were measured on 11 occasions: three times before dosing (baseline) and on days 3, 7, 10, 14, 19, 24 and 28 and at day 56 (i.e., 28 days after stopping teriparatide ). During the first 2 days of teriparatide treatment, PINP levels increased rapidly, by 8.2% (90% confidence interval (CI) 6.9%, 9.5%) and continued to increase until the end of treatment to 110.8%. PICP and OC showed a similar, but less pronounced, pattern. All three markers increased by at least 75% at day 28. A small, transient decrease in bone resorption markers occurred over the same period. Following cessation of treatment, concentrations of bone formation markers decreased to within 20% of baseline values by day 56. In conclusion, the bone formation markers PINP, PICP and OC show a rapid and robust increase in response to teriparatide, which is noticeable during the first week of therapy. PINP is the most responsive marker. These findings have important implications for monitoring patients treated with teriparatide and may also inform the design of studies of new anabolic agents for osteoporosis.
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PMID:Rapid and robust response of biochemical markers of bone formation to teriparatide therapy. 1967 11

Bone turnover markers (BTM) progressively decrease in young adult women. This might be linked to changes in insulin-like growth factor-1 (IGF-I). Four serum BTMs [serum C-telopeptide of type 1 collagen (CTX), osteocalcin (OC), N-terminal propeptide of type 1 procollagen (P1NP), and bone alkaline phosphatase (bone AP)], serum calcium (sCa), phosphate (sPO(4)), magnesium, 25-hydroxyvitamin D [25(OH)D], intact parathyroid hormone (PTH) and IGF-I were measured in 531 young healthy premenopausal women aged 20-50 years participating in the BONTURNO study. In all subjects bone mineral density (BMD) was measured at the spine and at the hip by dual-energy X-ray densitometry. Hip BMD, IGF-I, the four BTMs, sCa and sPO(4) progressively decreased with advancing age and this was associated with proportional increases in PTH. IGF-I levels were significantly and positively correlated with sCa, sPO(4), CTX, OC, P1NP, bone AP, spine BMD, femoral neck BMD and total hip BMD and negatively with age, BMI and serum PTH. When the IGF-I levels were adjusted for age and BMI, the only correlations maintaining a statistical significance were those with serum PTH, P1NP and bone AP. These associations were weak and IGF-I accounted for a only a small proportion of the BTM variance. The mean, age-adjusted IGF-I values were significantly higher in women practicing physical exercises for more then 60 min per week than in sedentary women. In conclusion, in this study we provide evidence of an association between the age-related decline in IGF-I with the progressive decrease in bone formation markers in premenopausal women.
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PMID:Insulin-like growth factor-1 is associated with bone formation markers, PTH and bone mineral density in healthy premenopausal women. 1985 71

Calcium and vitamin D are essential for bone growth; milk is an appropriate vehicle to be fortified with calcium, vitamin D and other minerals. The purpose of the current study was to compare the effect of supplementing with a high calcium milk drink with added vitamin D, magnesium and zinc (HCM) versus a placebo drink on serum parathyroid hormone (PTH) and vitamin D status as well as markers of bone formation/resorption in postmenopausal women living in South East Asia (Jakarta, Indonesia and Manila, the Philippines) over a period of 4 months. Calcium intake at baseline was 237 mg (median; 176-316, interquartile range) for Indonesia and 353 mg (median; 222-480, interquartile range) for the Filipino women per day. Fortified milk supplementation reduced the percentage of women that were insufficient in 25 (OH) vitamin D(3) (<50 nmol/L) from 70% to 22% in the Indonesian women and 20% to 0% in the Filipino women. Fortified milk supplementation significantly reduced parathyroid hormone levels (PTH) by week 2 (22% and 11%), C-telopeptide of type I collagen (CTX) by week 2 (34% and 27%), osteocalcin (OC) by week 8 (18% and 25%) and procollagen type I N-propeptide (PINP) by week 8 (15% and 21%), in women from Indonesia and the Philippines, respectively. Thus, the HCM intervention was able to significantly improve vitamin D status, lower PTH levels and reduce bone turnover in two groups of South East Asian women.
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PMID:The effect of a fortified milk drink on vitamin D status and bone turnover in post-menopausal women from South East Asia. 1989 12

The role of type 2 deiodinase (D2) in the human skeleton remains unclear. The D2 polymorphism Thr92Ala has been associated with lower enzymatic activity, which could result in lower local triiodothyronine (T(3)) availability in bone. We therefore hypothesized that the D2 Thr92Ala polymorphism may influence bone mineral density (BMD) and bone turnover. We studied 154 patients (29 men, 125 women: 79 estrogen-replete, 46 estrogen-deficient) with cured differentiated thyroid carcinoma. BMD and bone turnover markers [bone-specific alkaline phosphatase (BAP), cross-linking terminal C-telopeptide of type I collagen (CTX), procollagen type 1 amino-terminal propeptide (P1NP), and cross-linked N-telopeptide of type I collagen (NTX)] were measured. Effects of the D2 Thr92Ala polymorphism on BMD and bone turnover markers were assessed by a linear regression model, with age, gender, estrogen state, body mass index (BMI), serum calcium, 25-hydroxyvitamin D, parathyroid hormone (PTH), thyroid-stimulating hormone (TSH), and free triiodothyroxine (T(4)) as covariables. Sixty patients were wild type (Thr/Thr), 66 were heterozygous (Thr/Ala), and 28 were homozygous (Ala/Ala) for the D2 polymorphism. There were no significant differences in any covariables between the three genotypes. Subjects carrying the D2 Thr92Ala polymorphism had consistently lower femoral neck and total hip densities than wild-type subjects (p = .028), and this was accompanied by significantly higher serum P1NP and CTX and urinary NTX/creatinine levels. We conclude that in patients with cured differentiated thyroid carcinoma, the D2 Thr92Ala polymorphism is associated with a decreased femoral neck BMD and higher bone turnover independent of serum thyroid hormone levels, which points to a potential functional role for D2 in bone.
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PMID:The type 2 deiodinase Thr92Ala polymorphism is associated with increased bone turnover and decreased femoral neck bone mineral density. 2020 Sep 41

This study was purposed to investigate the short-term effects of citrate administration on bone metabolism in the healthy blood donor volunteers. A crossover, placebo-controlled trial were conducted on 22 healthy blood donor volunteers. The volunteers received either a standardized infusion of citrate at 1.5 mg/(kg.min) or the equal volume of placebo normal saline, were washout for 2-3 weeks. During washout serial blood samples were collected and analyzed for bone biochemical markers and electrolytes, such as bone formation marker osteocalcin (OC), bone resorption marker carboxyterminal telopeptide of type I collagen (CTX), intact parathyroid hormone ((i)PTH), ionized calcium ((i)Ca(2+)) and phosphorus (P(i)). Serial urine samples were collected and analyzed for Ca(2+), P(i) and creatinine concentration. The results showed that compared with placebo group, infusion of citrate increased serum levels of OC and CTX (p < 0.0001). The greatest increase of OC and CTX levels occurred at the completion of the intervention. The increment of CTX was higher than OC (p = 0.02), and the OC/CTX ratio decreased (p < 0.01). Infusion of citrate also induced profound increase in serum (i)PTH level (p < 0.0001) and urinary calcium excretion (p < 0.0001), and decrease in serum (i)Ca(2+) (p < 0.0001) and P(i) (p < 0.01) levels. The decrease of (i)Ca(2+) level in female was higher than that in male (p = 0.007), but the changes of (i)PTH, OC, and CTX levels showed no differences between female and male. Changes of OC and CTX levels were closely related to each other (r = 0.56, p < 0.0001) and changes of both markers were negatively correlated with the change of serum (i)Ca(2+) concentration during the citrate intervention(r(OC) = -0.44, r(CTX) = -0.44, p < 0.0001). Increased levels of (i)PTH showed positively correlation with OC (r = 0.34, p = 0.02) and borderline correlation with CTX (r = 0.29, p = 0.06) in male. No such relationship was observed in female. All bone markers and electrolyte levels returned to baseline within 24 hours. It is concluded that the citrate load at the dose as a single platelet apheresis results in profound increase of bone turnover, which is characterized by a short-term increase of bone resorption and excretion of calcium. The possible effect of citrate on bone mass of long-term frequent platelet apheresis donor is worth concerning.
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PMID:[Short-term effects of citrate on markers of bone metabolism in Chinese blood donor volunteers]. 2056 51


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