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)

Serum vitamin D metabolites and urinary calcium excretion; parameters of bone formation (serum alkaline phosphatase, serum osteocalcin); parameters of bone resorption (24 hour hydroxyprolinuria, 2 hour fasting urinary hydroxyproline/creatinine ratio); and parameters of cortical and trabecular bone density, parathyroid hormone (iPTH, COOH terminal assay), and serum minerals (calcium, phosphorus) were followed serially in 55 young adults (21 women and 34 men) from December 1985 until January 1987 at four different times during the year. The effect of a low-dose cyclooxygenase inhibitor (piroxicam 5 mg daily) on the same parameters of bone density and bone turnover when given from December until May, was also evaluated in this study. At the end of the treatment period parameters of bone turnover and bone density were comparable between placebo and piroxicam-treated groups. Therefore, the results of all subjects were pooled in order to investigate seasonal variation. In both sexes, seasonal variation was found not only for 250HD3 but also for 1,25(OH)2D3, serum calcium and phosphorus, urinary calcium excretion, and for bone density at the lumbar spine. Parameters of bone formation (serum osteocalcin and alkaline phosphatase), bone resorption (24 hour urinary hydroxyprolinuria and fasting urinary hydroxyproline/creatinine ratio) and PTH were influenced by this seasonal variation. We conclude that in young adults, a significant seasonal variation occurs, with low winter and high summer values, for serum 25 and 1,25(OH)2D3 for urinary calcium apparently without important influence on parameters of bone turnover or parathyroid activity and for lumbar spine density. Treatment with a low-dose cyclooxygenase inhibitor was without influence on the observed changes.
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PMID:Seasonal variation in bone metabolism in young healthy subjects. 165 77

Adenosine contracts pregnant and nonpregnant guinea pig myometrial smooth muscle (MSM). We have 1) described dissociation of A1-adenosine receptors from adenylate cyclase inhibition in nonpregnant MSM (M. A. Smith, J. L. Silverstein, D. P. Westfall, and I. L. O. Buxton, Cell. Signal. 1: 357-365, 1989); 2) described appearance of such inhibitory coupling in pregnant MSM [W. P. Schiemann, D. P. Westfall, and I. L. O. Buxton, Am. J. Physiol. 261 (Endocrinol. Metab. 24): E141-E150, 1991]; and 3) demonstrated a role for myometrial A1 receptors in the rapid formation of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in nonpregnant MSM and the cyclooxygenase dependence of this effect (W. P. Schiemann, K. O. Doggwiller, and I. L. O. Buxton. J. Pharmacol. Exp. Ther. 258: 429-437, 1991). To further characterize adenosine action in pregnant tissue, we explored A1 coupling to increased phosphoinositide hydrolysis in near-term pregnant MSM. The A1-receptor agonist (+)-N6-(2-phenylisopropyl)adenosine stimulates the rapid dose-dependent formation of Ins(1,4,5)P3 and stimulates rapid degradation of uterine inositol monophosphates (InsP) in a manner paralleling increases in inositol polyphosphates. Both A1-mediated responses were blocked by the A1 antagonist 8-(p-sulfophenyl)theophylline, and, unlike the effect observed in nonpregnant MSM, treatment of pregnant MSM with either meclofenamate or indomethacin failed to block A1-mediated increases in Ins(1,4,5)P3. Pretreatment of MSM with either Li+ or pertussis toxin failed to alter either Ins(1,4,5)P3 formation or InsP degradation. Furthermore, assay of inositol phosphomonoesterase (InsPase) activity in the presence or absence of Li+ confirmed the existence of an MSM Li(+)-insensitive InsPase enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adenosine A1-receptor coupling to phosphoinositide metabolism in pregnant guinea pig myometrium. 165 16

We investigated the effects that the combination of IL-1 alpha and transforming growth factor-beta (TGF-beta) had on PGE2 production in a murine clonal osteoblastic cell line MC3T3-E1 and primary rat calvarial osteoblast-like cells. In serum-supplemented medium, IL-1 alpha was a potent stimulator of PGE2 production in MC3T3-E1 cells (50-fold increase with 0.1 ng/ml). TGF-beta (10 ng/ml) had only a small effect alone and no additional effect on IL-1 alpha-induced responses. In serum-deprived MC3T3-E1 cells, PGE2 responses to IL-1 alpha were either absent or markedly reduced. TGF-beta alone had small effects. However, simultaneous addition of TGF-beta with IL-1 alpha to MC3T3-E1 cells partially restored the ability of IL-1 alpha to generate a PGE2 response (10-fold increase in PGE2 with 0.1 ng/ml of both IL-1 alpha and TGF-beta). As with MC3T3-E1 cells, serum-deprived primary fetal rat calvarial osteoblastic cells also did not respond to IL-1 alpha, unless TGF-beta was present in the medium (sixfold increase in PGE2 with 0.1 ng/ml IL-1 alpha and 10 ng/ml TGF-beta). The synergistic effect of TGF-beta and IL-1 alpha was specific for PGE2 responses, because these factors did not synergistically affect cell proliferation, collagen and noncollagen protein synthesis, or alkaline phosphatase activity. The observed synergy was not associated with changes in the steady state cyclooxygenase (PGH synthase) mRNA levels. However, it did correlate with increased release of [3H]arachidonic acid from prelabeled serum-depleted MC3T3-E1 cells. Hence, the synergistic interactions of IL-1 alpha and TGF-beta on PGE2 appear to occur through an increase in the release of arachidonic acid substrate from phospholipid pools. These effects may be important for both normal bone turnover and the responses of bone to inflammatory and immune stimuli.
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PMID:Effects of transforming growth factor-beta and IL-1 alpha on prostaglandin synthesis in serum-deprived osteoblastic cells. 170 13

Cytokines released at sites of inflammation and infection may alter normal bone remodeling processes resulting in pathologic bone destruction or bone formation. Interleukin 1, an inflammatory mediator, has been shown to stimulate as well as inhibit parameters associated with bone formation. In this study we have examined temporal aspects of the biphasic effects of recombinant interleukin 1 alpha (IL 1 alpha) on the differentiation of osteoprogenitor cells into bone-forming osteoblasts (bone nodules) in vitro. A dose-dependent stimulation of bone formation over a concentration range of 0.5 to 50 U/mL (1.4 x 10(-12) to 1.4 x 10(-10) M) was observed when preconfluent, primary cultures of fetal rat calvaria (RC) cells were pulsed with IL 1 alpha for 72 to 96 hr from the beginning of the culture period. This was correlated with a stimulation of cell proliferation and alkaline phosphatase activity measured during the late log phase of growth. In contrast, continuous exposure to IL 1 alpha or exposure to IL 1 alpha after confluency resulted in inhibition of bone nodule formation and alkaline phosphatase activity. IL 1 alpha-stimulated prostaglandin E2 (PGE2) production until the RC cells became multilayered, but the addition of the cyclooxygenase inhibitor indomethacin had no effect in reducing the IL 1 alpha-mediated stimulation of cell proliferation or bone nodule formation. However, in cultures continuously exposed to IL 1 alpha, added indomethacin partially reduced the inhibition of bone formation, suggesting that prostaglandin production may play a role in the inhibitory effects of IL 1 alpha on bone formation.
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PMID:Temporal sequence of interleukin 1 alpha-mediated stimulation and inhibition of bone formation by isolated fetal rat calvaria cells in vitro. 210 36

To elucidate the significance of endogenous prostaglandin E2 (PGE2) in osteoblastic cell function, we studied the effects of cyclooxygenase inhibitors on cell growth and alkaline phosphatase (ALP) activity in MC3T3-E1 cells. UMR-106 cells were also used as references in our experiments. MC3T3-E1 cells, cultured in alpha-minimal essential medium containing 10% fetal bovine serum, were shown to produce PGE2, which was markedly suppressed in the presence of indomethacin. Addition of indomethacin resulted in an increase in DNA content and [3H]thymidine incorporation. A similar growth stimulatory effect was observed when structurally different cyclooxygenase inhibitors, that is, acetyl salicylic acid (ASA), flurbiprofen, and piroxicam, were added. These cyclooxygenase inhibitors, however, differed in their effects on ALP activity. Indomethacin and ASA enhanced ALP activity, whereas flurbiprofen and piroxicam suppressed it. We then examined the effects of exogenous addition of PGE2. Although exogenous PGE2 at 6 x 10(-6) M slightly stimulated cell growth, it inhibited cell growth at 6 x 10(-8) M and 6 x 10(-7) M. ALP activity was reduced in a dose-dependent fashion by exogenous PGE2. These results suggest that PGE2 produced by MC3T3-E1 may be suppressing cell proliferation and that cyclooxygenase inhibitors, per se, may stimulate cell growth by inhibiting endogenous PGE2 production in MC3T3-E1 cells. UMR-106 cells also produced PGE2, although less than MC3T3-E1 cells. In UMR-106 cells, the cyclooxygenase inhibitors did not influence DNA content or ALP activity as distinctly as in MC3T3-E1 cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cyclooxygenase inhibitors enhance cell growth in an osteoblastic cell line, MC3T3-E1. 251 Apr 69

Recent studies have suggested that interleukin-1 or tumor necrosis factor-stimulated bone resorption is mediated by osteoclast-activating factor elaborated by osteoblastic cells. Since recombinant interferon gamma inhibits stimulation of bone resorption by these cytokines, we examined here the effects of recombinant human interferon gamma (rhIFN-G) on DNA synthesis and alkaline phosphatase (ALP) activity of a human osteoblastic osteosarcoma cell line, SaOS2, under preconfluent culture conditions. Addition of rhIFN-G to the cells markedly inhibited their DNA synthesis and ALP activity in a dose-dependent fashion. However, the inhibition was not dependent on the culture time. The highest inhibitory effect was observed in 10% serum-containing culture medium. The inhibitory effect on DNA synthesis was not eliminated by addition of indomethacin, a cyclooxygenase inhibitor. Furthermore, combination of rhIFN-G and recombinant human tumor necrosis factor alpha inhibited their DNA synthesis and the ALP activity in synergistic fashion. Therefore, these data suggest that rhIFN-G is a potent inhibitor for human osteoblastic cells.
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PMID:[Inhibitory effect of recombinant human interferon gamma on human osteoblastic osteosarcoma cells (SaOS2)]. 251 49

The Ca2+ ionophore A23187 (0.2-5 microM) stimulates the phosphorylation of the substrates of protein kinase C (40,000 dalton protein) and myosin light chain kinase (20,000 dalton protein) in the presence or absence of cyclooxygenase inhibitors. In the presence of cyclooxygenase inhibitors or millimolar Ca2+ there is no stimulation of phospholipase C by A23187. Fingerprints of the 32P-labeled 40,000 dalton protein isolated from platelets that have been stimulated with A23187, thrombin, phorbol 12,13-dibutyrate and 1,2-didecanoylglycerol were identical. Higher concentrations of A23187 (1-5 microM) induced the loss of polyphosphoinositides through phosphomonoesterase activity.
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PMID:Ionophore A23187 stimulates phosphorylation of the 40,000 dalton protein in human platelets without phospholipase C activation. 301 50

Prostaglandin (PG) E2, known as a bone-resorption factor, was released as a predominant arachidonate metabolite in the culture medium of an osteoblastic cell line cloned from mouse calvaria (MC3T3-E1). Epidermal growth factor (EGF) (10 ng/ml) prominently enhanced endogenous PGE2 synthesis, requiring the simultaneous presence of unidentified factor(s) contained in bovine serum. PGE2 synthesis increased after a lag phase for 1-2 h and reached a maximum level at about 3 h after EGF addition. EGF-stimulated PGE2 synthesis was almost completely blocked by 10 microM cycloheximide or 1 microM actinomycin D. Furthermore, when the cells were pretreated with EGF, the microsomes exhibited an increased activity of fatty acid cyclooxygenase (arachidonic acid----PGH2), whereas the activity of PGE synthase (PGH2----PGE2) remained unchanged. These results suggested an EGF-mediated induction of cyclooxygenase. Following increased PGE2 synthesis, DNA synthesis increased and alkaline phosphatase activity decreased in a slower response to EGF. PGE2 (above 0.1 microM) added to the cells could replace EGF. However, such effects of EGF on the osteoblasts could not be attributed totally to an autocrine function of PGE2 produced by stimulation with EGF because these effects of EGF were not abolished by indomethacin, which blocked the PGE2 synthesis.
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PMID:Stimulation of prostaglandin E2 synthesis in cloned osteoblastic cells of mouse (MC3T3-E1) by epidermal growth factor. 309 86

Recombinant human interleukin 1 (rhIL-1)alpha and rhIL-1 beta were examined for their effects on DNA synthesis, cell growth and alkaline phosphatase activity of the mouse osteoblastic cell line MC3T3-E1. The relative activity of rhIL-1 alpha and rhIL-1 beta was compared in terms of the units which induced half-maximal [3H]thymidine uptake into mouse thymocyte cultures exposed to IL-1. Both rhIL-1 alpha and rhIL-1 beta significantly inhibited DNA synthesis and division of the cells in a concentration- and cultivation time-dependent fashion. In contrast, rhIL-1 alpha and rhIL-1 beta markedly increased alkaline phosphatase activity, which is a marker of osteoblastic differentiation. This activity in cells treated with rhIL-1 alpha and rhIL-1 beta increased about 2.0- and 1.7-fold, respectively, compared with that of control cultures. Inhibition of the DNA synthesis and stimulation of alkaline phosphatase activity by both types of rhIL-1 were completely neutralized by treatment with their respective polyclonal antisera. Also, inhibition of DNA synthesis was unaffected by the addition of cyclooxygenase and lipoxygenase inhibitors, and stimulation of alkaline phosphatase activity was unaffected by the addition of indomethacin. These results indicate that both rhIL-1 alpha and rhIL-1 beta have qualitatively similar biological effects on osteoblastic cells. They also suggest that IL-1 is an important modulator of the growth and differentiation of osteoblasts.
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PMID:Effects of recombinant human interleukin 1 alpha and interleukin 1 beta on cell growth and alkaline phosphatase of the mouse osteoblastic cell line MC3T3-E1. 328 95

We studied arachidonic acid (AA) metabolism by a cell suspension containing principally cells of the thick ascending limb of the loop of Henle (TALH) obtained from the inner stripe of the outer medulla of the rabbit kidney. Based on comparison of specific activities of enzymes before and after separation, alkaline phosphatase, Na+-K+-adenosine triphosphatase, as well as Tamm-Horsfall glycoprotein and electron microscopic appearance, 80% of these cells were estimated to be TALH in origin. TALH cells had low activity of cyclooxygenase and did not show evidence of lipoxygenase activity. However, they selectively converted exogenous AA to oxygenated metabolites by a cytochrome P-450 related mechanism. AA metabolites were produced in large amounts (30-40% conversion of [14C]AA, 1 to 5 micrograms/mg of protein/30 min) and were increased 5-fold after separation of TALH cells from a suspension of outer medullary cells, suggesting that TALH cells synthesized these metabolites. Induction of cytochrome P-450 by pretreatment of rabbits with beta-naphthoflavone and 3-methylcholanthrene increased formation of the AA metabolites by almost 2-fold in the separated cells and correlated with cytochrome P-450 content of the renal outer medulla. Additionally, SKF 525A and carbon monoxide inhibited product formation in these renomedullary cells, supporting a role for a cytochrome P-450-like monooxygenase in TALH cell function.
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PMID:Arachidonic acid metabolism in a cell suspension isolated from rabbit renal outer medulla. 643 72


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