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

---

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

Daily subcutaneous injections of rat derived growth hormone to immature, hypophysectomized rats stimulated significant increases in body weight gain, serum osteocalcin, skeletal alkaline phosphatase and incorporation of radioactive thymidine and proline into the compact bone of femurs and tibiae. Equimolar doses of insulin-like growth factor-II did not produce similar biological effects. The data support the contention that growth hormone at equimolar concentration is a stronger osteogenic agent than is insulin-like growth factor-II in vivo.
...
PMID:Growth hormone stimulates cortical bone formation in immature hypophysectomized rats. 157 75

It has been established that regenerating marrow induces an osteogenic response in distant skeletal sites and that this activity is mediated by factors released into the circulation by the healing tissue. In the present study we have characterized one of these factors, a 14 amino acid peptide named osteogenic growth peptide (OGP). Synthetic OGP, identical in structure to the native molecule, stimulates the proliferation and alkaline phosphatase activity of osteoblastic cells in vitro and increases bone mass in rats when injected in vivo. Immunoreactive OGP in high abundance is present physiologically in the serum, mainly in the form of an OGP-OGP binding protein complex. A marked increase in serum bound and unbound OGP accompanies the osteogenic phase of post-ablation marrow regeneration and associated systemic osteogenic response. Authentic OGP is identical to the C-terminus of histone H4 and shares a five residue motif with a T-cell receptor beta-chain V-region and the Bacillus subtilis outB locus. Since these latter proteins have not been implicated previously in the control of cell proliferation or differentiation, OGP may belong to a novel, heretofore unrecognized family of regulatory peptides. Perhaps more importantly, OGP appears to represent a new class of molecules involved in the systemic control of osteoblast proliferation and differentiation.
...
PMID:Histone H4-related osteogenic growth peptide (OGP): a novel circulating stimulator of osteoblastic activity. 158 15

The cartilagenous tissue of mandibular condyles of newborn mice contains progenitor cells as well as young and mature chondrogenic cells. During in vitro cultivation of the tissue, progenitor cells undergo osteogenic differentiation and form new bone (Silbermann, M., D. Lewinson, H. Gonen, M. A. Lizarbe, and K. von der Mark. 1983. Anat. Rec. 206:373-383). We have studied the expression of genes that typify osteogenic differentiation in mandibular condyles during in vitro cultivation. RNAs of the genes for collagen type I, osteonectin, alkaline phosphatase, and bone gla protein were sequentially expressed in progenitor cells and hypertrophic chondrocytes during culture. Osteopontin expression peaked in both the early and the late phase of the differentiation process. The data indicate a distinct sequence of expression of osteoblast-specific genes during osteogenic differentiation and new bone formation in mandibular condyles.
...
PMID:Gene expression during osteogenic differentiation in mandibular condyles in vitro. 169 Nov 90

The possibility that the non-osteogenic mouse pluripotent cell line, C3H10T1/2 (10T1/2), could be induced to differentiate into osteogenic cells by various hormones and cytokines was examined in vitro. Of a number of agents tested, recombinant human bone morphogenetic protein-2 (rhBMP-2) and retinoic acid induced alkaline phosphatase (ALP) activity in 10T1/2 cells. rhBMP-2 also induced mRNA expression of ALP in the cells. Dexamethasone, 1 alpha, 25-dihydroxyvitamin D3, transforming growth factor-beta 1 and insulin-like growth factor-I did not stimulate ALP activity. Treatment with rhBMP-2 greatly induced cAMP production in response to parathyroid hormone in 10T1/2 cells. No ALP activity was induced in NIH3T3 fibroblasts treated with rhBMP-2 or retinoic acid. These results indicate that 10T1/2 cells have a potential to differentiate into osteogenic cells under the control of BMP-2.
...
PMID:The non-osteogenic mouse pluripotent cell line, C3H10T1/2, is induced to differentiate into osteoblastic cells by recombinant human bone morphogenetic protein-2. 169 39

Specific binding sites for the peptide hormone somatostatin have previously been demonstrated in long bones from neonatal rats. In the present study, the distribution of somatostatin receptors during embryonic bone formation has been investigated using the stable radioiodinated somatostatin analogue, SDZ 204-090. Somatostatin receptors in rat long bones were first detectable at the time of invasion of the cartilage model by osteogenic cells. Initially, receptors were detectable throughout the region occupied by osteogenic cells. As bone growth proceeded, however, receptors were restricted to the region of most recent invasion of the hypertrophic cartilage, where osteoid had not yet been deposited. In vivo labelling studies in neonatal rats were carried out to identify the cells bearing somatostatin receptors. Receptors were present in a restricted region of the metaphysis, immediately adjacent to the hypertrophic cartilage. Chondrocytes, osteoclasts, and mature osteoblasts were not labelled by the radioligand. The labelled cells were often apposed to remnants of cartilage matrix and stained positively for the osteoblast marker, alkaline phosphatase. Thus the cells with specific somatostatin-binding sites were probably osteoblast precursor cells. Specific binding was detectable in all endochondral bones examined, including those of the skull, but no specific binding was found in the membrane bones of the skull. These data suggest that somatostatin is involved in the regulation of osteoblast differentiation during endochondral bone formation.
...
PMID:Somatostatin receptors are restricted to a subpopulation of osteoblast-like cells during endochondral bone formation. 171 2

The number of identifiable stages and expression of differentiation markers in cells of the osteoblast lineage are not well understood. In the present study, a mAb, designated rat bone marrow (RBM) 211.13, was prepared that stained selectively the osteogenic and preosteoblastic cells along the surfaces of bone in calvariae, femurs, and metatarsals. The staining was cell surface associated and coincided with that for alkaline phosphatase (APase) detected histochemically. Only cells positive for APase activity by biochemical assay and not those without APase activity (e.g., fetal rat skin) stained with RBM 211.13. By immunoblotting, RBM 211.13 recognized a band coinciding with APase activity on nonreducing/nondenaturing gels, and RBM 211.13 precipitated a protein which on reduced gels migrated with an apparent molecular mass of approximately 80 kD. RBM 211.13 labeling was abolished by phosphatidylinosital-specific phospholipase C, known to release APase from the cell surface. All of these data support the concept that RBM 211.13 recognizes the bone isoenzyme of APase. RBM 211.13 was used to sort by flow cytometry the APase-positive and APase-negative cells from mixed fetal rat calvaria (RC) cell populations. The osteoprogenitors we identified earlier that form bone nodules in vitro (Bellows, C. G., J. E. Aubin, J. N. M. Heersche, and M. E. Antosz. 1986. Calcif. Tissue Int. 36:143-154; Bellows, C. J., J. N. M. Heersche, and J. E. Aubin. 1990. Dev. Biol. 140:132-138) were found within the APase-positive pool. By immunopanning, RC cells were separated into APase-enriched (APase-positive, adherent) and APase-depleted (APase-negative, nonadherent) populations. The APase-positive fraction was enriched two-to-threefold for bone-forming osteoprogenitors compared to unfractionated cells, while the APase-negative population formed very few nodules under the same conditions. Both populations responded to the glucocorticoid dexamethasone (DEX) with an increase in bone nodule formation. However, the fold stimulation in bone formation in the APase-negative population was approximately 30-fold, while the fold stimulation in the APase-positive population was only approximately 5-fold. These data suggest that APase expression can be used for immunoselection to fractionate osteoblastic populations into an APase-positive population and a population initially APase-negative, that virtually all osteoprogenitors forming bone in vitro in the absence of added glucocorticoids reside in the APase-positive pool, and that the only osteoprogenitors present in the APase-negative pool are those requiring DEX to differentiate.
...
PMID:Positive and negative immunoselection for enrichment of two classes of osteoprogenitor cells. 171 92

Colony-forming efficiency (CFE) was used to monitor the proliferative response of alkaline phosphatase-positive rabbit bone marrow stromal cells to acute blood loss. The CFE of animals subjected to a 1% blood loss was 0.97 compared with 0.06 (p less than 0.01) in nonbled animals. Sera obtained from animals 10 days after an initial blood loss stimulated the CFE of marrow cultures from nonbled donors to the same degree as osteogenin. Erythropoietin and control sera (from nonbled animals) had no effect. Hence, acute blood loss and sera from bled animals stimulate proliferation of alkaline phosphatase-positive marrow stromal cell colonies. The agent(s) responsible is unknown but it is present in serum in response to blood loss. Confirmation of a specific effect on osteoprogenitor cells may warrant the designation "osteopoietin."
...
PMID:Colony-forming efficiency response of bone marrow stromal cells to acute blood loss. 172 34

Bone marrow stromal cells are a mixed population that contribute to the formation of the hematopoietic microenvironment. The osteogenic lineage includes populations of cells that, in culture, form discrete nodules of mineralized tissue when grown in the presence of ascorbic acid and sodium beta-glycerophosphate. We have used nodule formation to assay for the self-renewal capacity of osteoprogenitor cells in chick bone marrow cultures. To examine the regulatory influence of dexamethasone (Dx), first subcultures were grown continuously or split 1:1 at repeated subculture. Cells in continuous culture exhibited less than two population doublings, while cellular proliferation and alkaline phosphatase area were inhibited by 10(-8) mol/L Dx. Cells in split (redistributed) cultures exhibited up to 14 population doublings and cellular proliferation was also inhibited by Dx. In contrast with continuous cultures, redistributed cultures treated with Dx had increased alkaline phosphatase area and 15-fold larger amounts of mineralized tissue formation than controls. Osteogenesis was sustained for up to four subcultures and the ratio of mineralized tissue area to alkaline phosphotase positive cell area was at most 0.55. These data indicate that the osteogenic lineage of bone marrow stromal cells contains self-renewing progenitors that are recruited by Dx in culture and that at a maximum, only 55% of the alkaline phosphatase-positive cell population contributes to osteogenesis.
...
PMID:Dexamethasone recruitment of self-renewing osteoprogenitor cells in chick bone marrow stromal cell cultures. 173 81

The biologic effects of recombinant human bone morphogenetic protein-2b (BMP-2b = BMP-4) were studied and compared with transforming growth factor-beta 1 (TGF-beta 1) in fetal rat osteoblast-like (ROB) cells. Similar to the effects of TGF-beta 1, BMP-2b stimulated DNA and collagen synthesis as well as protein accumulation. Unlike TGF-beta 1, which inhibited alkaline phosphatase activity, BMP-2b enhanced enzyme activity eight-to ninefold over the control level. The present study demonstrates direct actions of BMP-2b on bone-associated cells to stimulate osteogenic phenotypes in vitro and provides a cellular mechanism for the induction of bone formation by BMP-2b in vivo.
...
PMID:Bone morphogenetic protein-2b stimulation of growth and osteogenic phenotypes in rat osteoblast-like cells: comparison with TGF-beta 1. 179 47

The mechanisms by which calcium (Ca2+) and inorganic phosphate (Pi) accumulate into matrix vesicles (MV) have not been elucidated. In the present study the characteristics of Pi uptake into MV isolated from mildly rachitic chicken growth plate cartilage have been investigated. The results indicate that Pi accumulates into MV mainly via a Na(+)-dependent Pi transport system. In the absence of NaCl in the extravesicular medium, Pi uptake was a nonsaturable process. In the presence of 150 mM NaCl, the initial rate of Pi uptake was 4.38 +/- 1.02-fold higher than with 150 mM choline chloride (mean +/- S.E., n = 8, p less than 0.005). Other cations showed partial activity to drive Pi into MV as compared to Na+:Li+ (64.4%) greater than K+ (39.8%) greater than choline (39.0%) greater than tetramethylammonium (30.0%) greater than N-methylglucamine (26.3%). Na(+)-dependent Pi transport activity displayed saturability towards increasing extra-vesicular concentrations of Na+ and Pi. The apparent Km for Pi was 0.68 +/- 0.16 mM. The Na+ concentration producing half-maximum Pi transport activity was 106.2 +/- 11.0 mM. Kinetic analysis suggests that Na+ interacts with the Pi carrier with a stoichiometry of more than one Na+ ion with one Pi molecule. In MV isolated from normal chicken growth plate cartilage, this Na(+)-dependent Pi transport system was barely expressed. In contrast to the effect on Pi uptake by MV, the activity of alkaline phosphatase was not changed when NaCl was substituted for choline chloride in the assay medium. In addition to this observation which suggests that this enzyme is not related to the Pi transport activity described in this study, levamisole, which inhibited alkaline phosphatase activity did not affect the Na(+)-dependent uptake of Pi. Both arsenate and phosphonoformic acid, two inhibitors of the epithelial Na(+)-dependent Pi transport systems, were active inhibitors of the Na(+)-dependent Pi uptake by MV with a higher potency for phosphonoformic acid. Associated with the expression of a facilitated Na(+)-coupled Pi transport in MV, in vitro calcification assessed by 45Ca2+ uptake also showed a marked dependence on extravesicular sodium. This relationship was markedly attenuated in MV isolated from normal chicken growth plate cartilage expressing a weak Na(+)-facilitated Pi transport activity. In conclusion, a saturable Na(+)-dependent Pi carrier has been characterized which facilitates Pi transport in MV. Its potential role for Ca-Pi accumulation into MV and subsequent development of vesicular calcification followed by mineralization of the osteogenic matrix is proposed and remains to be further investigated.
...
PMID:Characterization of a Pi transport system in cartilage matrix vesicles. Potential role in the calcification process. 183 87


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---