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)

Estrogen stimulates osteoblastic collagen production in vitro, but whether the same stimulation takes place in vivo is still unknown. To test the stimulatory effects of a combined estrogen-gestagen regimen in vivo we monitored serum levels of the carboxy-terminal propeptide of human type I procollagen (S-PICP) in a group of 12 osteoporotic women over a 150 week treatment period. Spinal bone mineral content (BMC) increased to a maximum of 5% over pretreatment values around week 90. Serum alkaline phosphatase (S-AP) and serum bone gla protein (S-BGP) both fell from initial values of 220 U/liter and 39 ng/ml, respectively, to 146 U/liter (p less than 0.01) and 27.2 ng/ml (NS) around week 60 and remained reduced over the remaining treatment period. S-PICP also fell from 117 to 68 micrograms/liter at week 60 and 70 micrograms/ml at week 150 (P less than 0.01). This is equal to a reduction to 32 +/- 10% pretreatment levels. The reduction in S-PICP was not significantly different from that of the other two markers of bone formation (S-AP and S-BGP). Thus, provided the metabolic clearance of PICP remains unaltered after hormone replacement therapy, no major stimulation of osteoblastic collagen type I synthesis was demonstrable during estrogen-gestagen treatment in this population of osteoporotic women. The changes in bone markers seen in this study are therefore consistent with an estrogen-mediated reduction in the frequency of remodeling activation. Because of the reduction in bone turnover and methodologic limitations of bone marker assays, however, smaller increases in the amount of bone formed per activation could remain undetectable.
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PMID:Effects of a combined estrogen-gestagen regimen on serum levels of the carboxy-terminal propeptide of human type I procollagen in osteoporosis. 172 40

Serum levels of osteocalcin [OC; bone Gla protein (BGP)] and bone alkaline phosphatase (B-AP) are both correlated to osteoblastic activity, which may be regulated by several hormones, including estrogen, 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], and PTH. Estrogen shows reproducible variations during the menstrual cycle, while available data on variations in serum 1,25-(OH)2D3 and serum immunoreactive PTH show midcyclic increases or no changes. In the present study we evaluated osteoblastic activity by measuring serum OC and B-AP during the menstrual cycle in eight healthy women, aged 20-47 yr. The cycles were synchronized by LH peaks, and follicular and luteal periods were normalized by lengths. Repeated measures analysis of variance showed that serum OC varied significantly (P less than 0.05), with highest levels during the luteal period. Although the same pattern was seen for serum B-AP, the variation just failed to reach significance (P less than 0.10), but the mean level was significantly higher during the luteal than during the follicular period (P less than 0.05). Gonadotropins and ovarian sex hormones showed significant variations. There were no significant changes in serum vitamin D-binding protein, serum total and free 1,25-(OH)2D3 index, or serum immunoreactive PTH-(1-84), but serum levels of somatomedin-C showed a significant variation, with the highest level during the luteal period (P less than 0.05). Blood levels and urinary excretion of minerals exhibited no significant variations. Cross-correlation studies between OC and estradiol showed the highest correlation coefficient, when OC was lagged about 7 days after estradiol (r = 0.69; P less than 0.05). Moreover, a high correlation was found between OC and somatomedin-C when matched at concurrent time points (r = 0.76; P less than 0.01). No significant correlations were found between the other calcium-regulating hormones and OC when matched at concurrent time points. In conclusion, we found a significant effect of the menstrual cycle on the serum levels of two osteoblastic bone markers, OC and B-AP. The changes indicated that osteoblastic activity is higher during the luteal period. However, whether the changes are caused by direct or indirect effects of the fluctuations in calciotropic hormones is still unresolved.
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PMID:Changes in biochemical markers of osteoblastic activity during the menstrual cycle. 211 May 77

Serum GH, E2, FSH, LH levels, bone mass, serum alkaline phosphatase (AKP), calcium levels and urinary calcium/creatine ratio in 42 postmenopausal women were compared with those in 30 women of fertile age. In thirteen out of the postmenopausal women we also observed these parameters before and after treatment with diethylstilbestrol (DES). The postmenopausal women had significantly reduced serum GH (P less than 0.01) and E2 levels (P less than 0.001) and increased serum FSH(P less than 0.001), LH levels (P less than 0.001), and had lower bone mass (P less than 0.01). They also had increased serum AKP levels (P less than 0.05) and urinary calcium/creatine ratio(P less than 0.01). There were positive correlations between serum E2 and GH levels, between postmenopausal bone loss and serum E2, GH decline. The postmenopausal bone loss began early as menopause commenced. After treatment with DES in 13 postmenopausal women, we observed that GH significantly increased (P less than 0.01) and FSH, LH decreased (P less than 0.001), AKP decreased by 27.58% and urinary calcium/creatine ratio decreased by 43.94% (compared with that before treatment). Our results indicate that bone turnover increased after menopause and resorption exceeded formation. There is bone loss in early postmenopause. The postmenopausal bone loss is related to serum GH, E2 levels. Estrogen replacement therapy is necessary in postmenopausal women and it should be given as early as possible. After treatment with DES, increased serum GH levels, decreased AKP values (27.58%) and urinary calcium/creatine ratio (43.94%) suggest that estrogen may play a definite role in bone metabolism through increased GH.
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PMID:[Relation of serum growth hormone and estradiol levels and osteoporosis in postmenopausal women]. 215 32

A cohort of 101 patients were treated with enteric-coated sodium fluoride tablets and calcium supplements. Vitamin D was also given in supra-physiologic doses in 70% of the cases. Lumbar bone mineral density (BMD), as measured by dual-photon absorptiometry, increased in a linear fashion up to four years, irrespective of the value of initial BMD and of the underlying condition, be it involutional osteoporosis (the vast majority), glucocorticoid osteoporosis, or even osteogenesis imperfecta. Estrogen replacement therapy (ERT) seemed to promote the fluoride-induced increase in lumbar BMD, as did the vitamin D supplements. Of these patients, 17% proved "resistant" to the therapy. There was no way of predicting who would be in this category. Compared with an age- and sex-matched control group, women showed significantly different behavior of their bone mass. In the control group, the losses were highly significant at the lumbar spine and at all three scanning sites of the forearm, as measured by single-photon absorptiometry. In contrast, the fluoride group had a significant gain of BMD at the lumbar spine and changes of BMC at the forearm were not significant. Fluoride thus preserved bone mass at the appendicular skeleton, while increasing it at the axial skeleton. When comparing the patients who received vitamin D supplements and those who did not, there was a significant difference in the appendicular skeleton. The distal forearm in the vitamin D-supplemented group tended to gain, whereas the midforearm lost significant bone mass. The trend was reversed in the group without vitamin D-supplementation, a more favorable pattern. Therefore, vitamin D supplements should not, as a rule, be provided to such patients. The biochemical hallmark of the fluoride-induced changes is a slight rise of the alkaline phosphatase within the normal range. Alkaline phosphatase levels that exceed the upper limit of normal signal a warning that too much fluoride and/or too little calcium supplements are being administered, or that a fluoride-related complication is impending or has occurred (e.g., a stress fracture). Osteosclerosis was achieved in 69% of the cases who had a radiological followup of at least four years (average period of appearance: 1.8 years). Stress fractures in the lower limbs occurred in 17 patients, almost exclusively in females, and appeared on average 2.2 years after initiation of therapy. In this group of stress fractures there was significant cortical bone loss at midforearm.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Treatment of the vertebral crush fracture syndrome with enteric-coated sodium fluoride tablets and calcium supplements. 218 27

Estrogen is important for both the sexual dimorphism of the skeleton during growth and the maintenance of bone balance in adults. This report describes the in vivo effects of estrogen on bone formation and gene expression in the tibial diaphysis of ovariectomized rats. Rats were ovariectomized at 8 weeks of age and were given diethylstilbestrol (DES) or placebo 1 week later as sc sustained release pellets. Histomorphometry revealed that that the periosteal bone formation and apposition rates were reduced at the tibial diaphysis 1 week after beginning estrogen treatment and further reduced after 2 weeks. Interestingly, DES treatment had no effect on endosteal bone formation, but suppressed endosteal bone resorption. Northern analysis of freshly isolated periosteal cells from tibiae and femora revealed that DES treatment resulted in dramatic decreases in steady state mRNA levels for the bone matrix proteins osteocalcin, prepro alpha 2(I) chain of type 1 collagen, osteonectin, and osteopontin as well as the osteoblast marker enzyme alkaline phosphatase. The results suggest that the inhibitory effects of estrogen on radial bone growth in rats are mediated, or at least accompanied, by the inhibition of the expression of bone matrix protein genes in periosteal cells.
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PMID:Estrogen inhibition of periosteal bone formation in rat long bones: down-regulation of gene expression for bone matrix proteins. 238 57

The effect of two different doses of ethinyl estradiol and norgestrel combined oral contraceptives (OCs) on hepatic functions of albino rats was studied for a period of six months. Combined OCs treatment caused an increase in glycogen, RNA, total lipids, triglycerides, cholesterol and free fatty acids contents of liver and liver microsomes and decreased the liver weight/body weight ratio and phospholipid contents. Liver aminotransferase activities were elevated in the OCs treated animals whereas alkaline phosphatase activity remained unchanged. The biochemical changes were found to be dose dependent. Thus the present study has shown that the combined OCs treatment for six months is associated with altered hepatic functions. The possible mechanism of such an alteration of hepatic functions on OCs treatment is discussed.
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PMID:Effect of combined ethinyl estradiol and norgestrel oral contraceptives on hepatic functions of albino rats. 241 11

Postmenopausal women lose bone mineral density and this loss can be prevented by estrogen administration. Although the skeletal effects of estrogens have been regarded previously as indirect, estrogen receptors have been discovered in cultured human osteoblasts and related cell lines. The UMR106 cell line derived from a rat osteogenic osteosarcoma is such an osteoblast model. We have shown direct effects of estradiol (E) on these cells in vitro, inhibiting growth and stimulating alkaline phosphatase activity (AP) corrected for cell number. This response was maximal at E conc. of 10(-10) M in serum and Phenol Red free medium, was metabolite specific and cell cycle-dependent. These cells contain high affinity binding sites with a Kd of 0.5 nM. Estrogen receptors were detected by the monoclonal antibody H-222 on Western blot after initial immunoprecipitation to concentrate the proteins. E treatment increased several enzymes including creatine kinase and LDH isoenzymes along with increments in intracellular transferrin. Transforming growth factor-beta is secreted by these cells. Secretion of this peptide was stimulated by E. TGF-beta mediated the transient growth inhibition associated with E treatment. Insulin like growth factors (IGF) are also secreted by these cells with IGF-II concentrations in the culture medium being eight times higher than IGF-I levels. E treatment increased the concentrations of both IGFs in the culture medium after a 3 day incubation. Exposure of E treated cells manifested a mitogenic response and reduced AP, indicating that E induced receptors for IGFs. These findings establish direct effects of E on osteoblastic cells in vitro and demonstrate responses to E at many levels. These osteoblast responses in vitro suggest an important role for sex steroids in the development and function of the osteoblast lineage.
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PMID:Estrogens and the skeleton: cellular and molecular mechanisms. 262 18

Estrogen (E) therapy and administration of oral contraceptives (OC) reportedly increase plasma calcitonin (CT) concentrations in women, effects said to mediate in part the beneficial actions of E on bone. To further examine this theory, we tested the effects of three cycles of OC therapy in 12 young women, comparing them to 10 healthy women before and after three normal menstrual cycles. We also determined the effects of 3 months of E therapy (ethinyl estradiol, 20 micrograms/day, 25 of 30 days) in 14 healthy postmenopausal women, using a crossover design (studied after 3 months with and 3 months without E). We determined CT by radioimmunoassay (antiserum G-1701) in whole plasma (iCT) and silica cartridge extracts of plasma (exCT) after overnight fasting, after calcium (Ca) infusion (2 mg Ca/kg over 5 minutes), and during a normal day at 0800, 1200, 1700, and 2000 h. In no control study was there a significant diurnal change in iCT or exCT, and neither OC nor E therapy altered this. Similarly, OC administration did not affect basal CT levels or the normal iCT and exCT responses to Ca infusion. E therapy induced expected changes in serum Ca, phosphorus, and alkaline phosphatase and urinary Ca and cAMP excretion; basal and diurnal plasma exCT levels were decreased significantly, consonant with the decrement in serum Ca. E did not alter normal iCT and exCT responses to Ca infusion. Thus, administration of either OC or E has no stimulatory effect on CT secretion, which suggests that the beneficial actions of E on bone are not mediated through CT-induced inhibition of bone resorption.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of oral contraceptive and estrogen administration on plasma calcitonin in pre- and postmenopausal women. 271 83

A comparative study of the metabolic effects of two combined oral contraceptive preparations was undertaken in seven WHO Collaborating Centres for Research in Human Reproduction. A total of 847 subjects were randomly allocated to one of two pill groups - norethisterone lmg/ethinyl estradiol 35 micrograms (NET/EE) or levonorgestrel 150 micrograms/ethinyl estradiol 30 micrograms (LNG/EE). An additional 195 women using an IUD served as a comparison group. Blood samples were taken on admission, and at 3 and 12 months thereafter. Both pills induced changes in fasting and 2-hour glucose, triglycerides, total cholesterol, HDL-cholesterol, bilirubin, alkaline phosphatase, albumin, and total protein, but not aspartate aminotransferase. The most dramatic and probably most clinically important changes were an increase in triglycerides and a decrease in HDL-cholesterol. The NET/EE preparation appeared to induce a greater increase in triglycerides, but no significant difference was found between the two pill preparations with respect to HDL-cholesterol changes.
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PMID:A randomized double-blind study of the effects of two low-dose combined oral contraceptives on biochemical aspects. Report from a seven-centred study. WHO Special Programme of Research, Development and Research Training in Human Reproduction. Task force on Oral Contraceptives. 286 58

The repeated observation of a fall in serum enzymes at midmenstrual cycle in an untreated patient with primary biliary cirrhosis stimulated a study of estrogen administration in five patients with primary biliary cirrhosis. One patient was premenopausal, one patient was postmenopausal and three had had oophorectomy. After 2 weeks of ethinyl estradiol, AST was under 100 IU per dl in all and had decreased by 50% or more in 4 of 5 patients. gamma-glutamyltransferase and alkaline phosphatase fell by 50 and 30% or more, respectively, in all patients. The decreases in serum enzymes were statistically significant in all patients for gamma-glutamyltransferase, in 4 of 5 for AST and in 3 of 5 for alkaline phosphatase. One patient developed increased icterus leading to withdrawal of estradiol. Withdrawal of estradiol was followed by return toward control values over variable periods, usually 1 to 4 weeks. Repeated courses of estradiol reproduced these enzyme changes. These observations indicate that estradiol in the doses used (0.05 mg per day) reversibly lowers serum enzyme values in biliary cirrhosis. The mechanism of the effect is unexplained, but an immune system alteration may be responsible.
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PMID:Effect of estradiol upon serum enzymes in primary biliary cirrhosis. 288 13


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