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)

Growth characteristics and the expression of trophoblast-associated markers by six cell lines generated from midgestation chorioallantoic placentas of outbred (Holtzman) and inbred (Lewis, PVG.RT Ir8) rats were evaluated. The cells comprising all cell lines were epithelioid (contained cytokeratin-type intermediate filaments), had normal (2n, 4n) DNA content, and synthesized the extracellular matrix glycoprotein laminin. Variability was observed among the lines in all other characteristics: median cell size, rate of growth, serum dependency, responses to transferrin and dibutyryl cyclic adenosine-3',5'-monophosphate, synthesis of some major proteins, alkaline phosphatase activity, and the expression of immunoreactive placental lactogen-II. In general, cell lines with smaller mean cell sizes grew rapidly and required little serum for maintenance in vitro; cell lines with larger mean sizes grew more slowly and preferred higher concentrations of serum. Some associations between mean cell size/rate of growth and other characteristics were observed. No major differences were apparent between cell lines generated from outbred and inbred rat placentas. Trophoblast cell lines expressing distinct phenotypes provide a valuable new approach for studying a wide range of trophoblast cell activities.
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PMID:Isolation of phenotypically distinct trophoblast cell lines from normal rat chorioallantoic placentas. 278 30

Two PRL-like glycoprotein hormone complexes were purified from the medium of cultured mouse conceptuses from day 10 of pregnancy: mouse placental lactogen-I (mPL-I) (29-32K), and mPL-I (36.5-42K). Sodium dodecyl sulfate-gel electrophoresis revealed that mPL-I (36.5-42K) is a complex of five proteins with mol wt of 36.5K, 37.5K, 39K, 40.5K, and 42K. Deglycosylation with peptide: N-glycosidase F or trifluoromethanesulfonic acid produced a single 29K protein. mPL-I (36.5-42K) was also sensitive to neuraminidase, but not to endo-beta-N-acetylglucosaminidase H or bacterial alkaline phosphatase. The production of intermediates from partial digestion of mPL-I (36.5-42K) with endo-beta-N-acetylglucosaminidase F indicated the presence of multiple glycosylation sites. mPL-I (29-32K) is a complex of three proteins with mol wt of 29K, 30.5K, and 32K. Treatment with peptide:N-glycosidase F or trifluoromethanesulfonic acid reduced the mol wt of the 30.5K and 32K bands to 28K. The 30.5K band was sensitive to endo-beta-N-acetylglucosaminidase H and endo-beta-N-acetylglucosaminidase F, but the 32K band was not. Neither band was sensitive to neuraminidase or bacterial alkaline phosphatase. The 29K band was resistant to all chemical and enzymatic treatments and is probably not glycosylated or phosphorylated. In the nonreduced state, neither form of mPL-I showed an increase in mobility over that of its reduced counterpart on sodium dodecyl sulfate-gel electrophoresis, indicating that neither form of mPL-I contains the large disulfide loop common to hormones of the PRL family. After iodination, all component proteins of both forms of mPL-I were found to bind to day 17 pregnant mouse liver membranes and were displaceable by excess mPL-II. In a radioreceptor assay, 125I-labeled mPL-I (36.5-42K) was displaced by mPRL or mPL-II, but not by mGH. An antiserum to both forms of mPL-I was generated, and a RIA employing mPL-I (36.5-42K) as the standard and radioligand was developed. Dilutions of day 10 pregnant maternal mouse serum and placental homogenate and a partially purified fraction of mPL-I (29-32K) produced displacement curves parallel to that of mPL-I (36.5-42K) standard curve. Five micrograms of mPRL, mPL-II, or mGH or 10 microliter day 17 pregnant or male mouse serum did not displace the radioligand from the antibody. mPL-I (36.5-42K) was lactogenic, but it did not possess LH-like bioactivity.
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PMID:Purification and partial characterization of two prolactin-like glycoprotein hormone complexes from the midpregnant mouse conceptus. 303 95

The dynamics of the release of human placental lactogen (hPL) under basal conditions and response to various secretogogues has been studied in perifused enriched hPL-producing cells from term placentae prepared by the isopycnic centrifugation of collagenase/hyaluronidase-dispersed placental cells on Percoll gradients. Under basal conditions, the perifused cells released hPL at a relatively constant rate for up to 24 h in culture. The mean rates of hPL release from cells (5 x 10(6) cells) from 18 normal full-term placentae varied from 1.8 to 20.2 ng/5 min (mean 7.7 ng/5 min). The cells from term placentae, however, did not release detectable amounts of chorionic gonadotrophin or the cytosolic enzymes lactic dehydrogenase and alkaline phosphatase. The amounts of hPL released by the perifused cells were inversely related to cell density with mean rates of hPL release by 2, 5, and 10 x 10(6) cells of 15.8, 8.6, and 5.7 ng/10(6) cells/0.5 h. The perifused cells responded to provocative stimuli (high-density lipoproteins (HDL), apolipoproteins AI, AII, and CI, partially purified hPL-releasing factor, phorbol esters, sn-1,2-diacylglycerol, and cAMP) in a manner qualitatively similar to enriched trophoblast cells and placental explants in static culture. Release of hPL in response to HDL, apoproteins AI, AII, and CI, and partially purified hPL-releasing factor was dose-dependent and occurred within 5 min of exposure. Basal and stimulated hPL release by perifused trophoblast cells that had been previously frozen at -70 degrees C for four weeks was identical to that of freshly dispersed cells from the same placenta. These experiments indicate that perifused trophoblast cells may be used as a model system to examine the dynamics of hPL release under basal conditions and in response to provocative stimuli.
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PMID:Characterization of placental lactogen release from perifused human trophoblast cells. 339 89

Activation of calcium-stimulated phospholipid-dependent protein kinase C (PKC) by diacylglycerols and phorbol esters has been shown to mediate the release of secretory proteins in several systems. To determine whether PKC activation is involved in regulation of the release of human placental lactogen (hPL) from the placenta, we examined the effects of various acylglycerols and phorbol esters on the release of hPL from cultured human trophoblast cells. Sn-1,2-dioctanoylglycerol (diC8) and phorbol-12-myristate-13-acetate (PMA), both of which stimulate placental protein kinase C activity, caused dose-dependent increases in hPL release over a 0.5-h period. The maximal amounts of hPL released in response to diC8 (300 microM) and PMA (10(-8) M) were 200-300% and 150-225% greater, respectively, than that released in response to diluent alone. Acylglycerols and phorbol esters, which are less potent stimulators of PKC activity in other systems, stimulated hPL release to a lesser extent than either diC8 or PMA. PKC-inactive acylglycerols and phorbol esters were without effect. After 0.5 h of exposure, diC8 (300 microM)- and PMA (10(-8) M)-exposed cells synthesized 257.5% and 250.3% more hPL than control cells. Cycloheximide at a dose (50 micrograms/ml) that inhibited the synthesis of trichloroacetic acid-precipitable [35S]methionyl placental proteins by more than 80% completely blocked the stimulatory effects of diC8 and PMA on hPL synthesis and release. Although diC8 and PMA stimulated the synthesis and release of hPL, these compounds had no effect on the release of hCG and did not cause the release of the cytosolic enzymes lactic dehydrogenase and alkaline phosphatase. The demonstration that acylglycerols and phorbol esters stimulate the synthesis and release of hPL strongly implicates protein kinase C activation in the mechanisms of hPL synthesis and release.
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PMID:Sn-1,2-diacylglycerols and phorbol esters stimulate the synthesis and release of human placental lactogen from placental cells: a role for protein kinase C. 373 65

The junctional and labyrinth regions of the rat chorioallantoic placenta during the second half of gestation showed different patterns of development with regard to DNA, protein, placental lactogen and alkaline phosphatase content. DNA and protein measurements indicated that growth of the labyrinth region was more rapid and persisted for longer during gestation than did growth in the junctional zone. At midpregnancy the junctional zone was the main source of placental lactogen whereas by late pregnancy both regions contributed considerable amounts. On Day 20 of gestation the labyrinth region contained significantly more placental lactogen than did the junctional zone. Alkaline phosphatase activity was predominant in the labyrinth zone throughout the second half of gestation. The results indicate that the chorioallantoic placenta is composed of two functionally distinct regions.
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PMID:Developmental changes in the intraplacental distribution of placental lactogen and alkaline phosphatase in the rat. 382 Jan 87

To detect antigens in the plasma of pregnant women that were not found in nonpregnant untreated normal women or males, highly sensitive immunodiffusion techniques with hyperimmune rabbit antiserum were used. The number of pregnancy-associated plasma constituents increased as pregnancy progressed in the 165 patients studied, with all 4 constituents usually seen in the third trimester. The 60 males and 111 nonpregnant women studied did not show any of these antigens. There were significant differences between second and third trimester reactions. (p less than .001). None of the antigens represented human chorionic gonadotropin, human placental lactogen, oxytocin, C-reactive protein, oxytocinase, alkaline phosphatase, or esterase. One of these constituents is present during combined estrogen-progesterone therapy.
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PMID:Antigenic constituents in pregnancy plasma which are undetectable in normal non-pregnant female or male plasma. 462 19

One of the requirements for enzyme immunoassay is the formation of a labelled component of the assay system which can be either the ligand or the binder. Three methods for conjugating alkaline phosphatase to human placental lactogen were investigated, involving water-soluble carbodiimide, glutaraldehyde, and the periodate oxidation technique. Of the 3, the periodate oxidation technique proved superior giving a conjugate with only slight changes in the Michaelis constant (Km) and maximum velocity (Vmax) which could be used for an enzyme immunoassay for human placental lactogen in human plasma.
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PMID:Comparison of three conjugation procedures for the formation of tracers for use in enzyme immunoassays. 608 61

In a series of 46 cases of primary mammary ductal carcinoma, immunohistochemical markers of differentiation (casein, human placental lactogen, alphalactalbumin, pregnancy specific beta-1 glycoprotein, secretory component, CEA, and peanut lectin agglutinins [PLA]), were quantitated via point-counting. An immunoperoxidase bridge (PAP) was used to identify all except the PLA, in which an avidin-biotin complex with alkaline phosphatase development was employed. For none of the markers was there any difference in the quantity present in tumors of patients who had recurred versus the tumors of patients who had enjoyed a minimum of five years disease-free survival. Nonneoplastic epithelium was only rarely positive for these markers. Although eventually surmounted, technical problems significantly hampered application of morphometry to this histochemical material. The authors conclude that these markers have little relationship to differentiation toward mammary duct epithelium and that they do not provide significant prognostic information in patients with breast cancer.
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PMID:Correlation of immunohistochemical markers with patient prognosis in breast carcinoma: a quantitative study. 609 96

Foeto-placental function and hormone levels in the maternal, foetal and amniotic compartments have been investigated in an acromegalic woman who was treated with 20 mg bromocriptine/day throughout gestation. Bromocriptine therapy during pregnancy had no effect on urinary oestriol excretion and plasma levels of unconjugated oestriol, progesterone, human placental lactogen, cystine aminopeptidase and heat-stable alkaline phosphatase. The maternal and foetal (cord )blood and amniotic fluid showed prolactin levels of 3.8, 6.5 and 1700 ng/ml, respectively, in the 39th week of pregnancy during bromocriptine therapy. Compared with data from normal pregnancies, these values demonstrated that bromocriptine or an active metabolite crossed the term placenta to suppress prolactin secretion from the foetal pituitary gland and that the prolactin level in amniotic fluid was scarcely affected by the drug. Maternal, foetal and amniotic fluid growth hormone levels were 27.0, 33.0 and 3.8 ng/ml, respectively, thus indicating that dopamine agonists suppress growth hormone only in acromegalic patients, and not in normal babies. Bromocriptine had no effect on thyroid-stimulating hormone concentrations in maternal, foetal and amniotic compartments.
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PMID:Successful pregnancy in an acromegalic patient during 2-Br-alpha-ergocryptine (CB-154) therapy. 714 32

Cell differentiation is supported much better by gels of extracellular matrix than by the same matrix provided as a rigid substrate. Many cell types including normal and malignant trophoblast cells, however, form multicellular multilayered aggregates on matrix gels with increased cell-to-cell contacts as compared to regular monolayers on rigid matrix substrates. In such cultures, it remained open, so far, whether stimulated expression of differentiation markers is caused by enhanced cell-to-cell communication or is displayed only by cells in direct contact to the gel. Therefore, choriocarcinoma cells (BeWo) were grown as aggregates: (a) on gels of the basement membrane-like Matrigel, (b) on plastic coated with poly-HEMA, or (c) as aggregates (spheroids) in suspension culture. Production of the differentiation marker chorionic gonadotropin was stimulated significantly in aggregates attached to gels of Matrigel or to the poly-HEMA substrate but not in suspended spheroids. With respect to cell-cell communications, however, expression of E-cadherin mRNA was not altered in any type of aggregates, as compared to control cultures on plastic. The expression of connexin43 mRNA (not of connexin26) was increased only in suspended spheroids, while microinjection of the fluorescent dye Lucifer Yellow suggested that cell communication via gap junctions was absent from cells grown as monolayers and was not induced in any type of aggregate. When cells were grown on gels of Matrigel, the relevance of direct cellular contact to the substrate for differentiation was analyzed by immunohistochemistry. Trophoblastic differentiation markers (chorionic gonadotropin, placental lactogen, placenta-type alkaline phosphatase, and pregnancy-specific glycoprotein beta 1) as well as the proliferation marker Ki-67 were not preferentially expressed in cells that were in contact with the gel. Similar random distributions of all these markers were also observed in spheroids cultured in suspension. The distributions of several matrix molecules and of different integrins were comparable between aggregates on matrix gels and those in suspension culture. According to these data, cell-cell communication appears to play a subordinate role for cytodifferentiation in cell aggregates on matrix gels, so that substrate anchorage and physical properties of the substrate may be the decisive factors. Interestingly, however, direct contact to the substrate does not seem to be essential for the stimulation of differentiation in cells on matrix gels. The results are discussed in the context of the "tensegrity"-model for cell-matrix interactions in which proper mechanical properties of the substrate are important for the regulation of cell differentiation by allowing a balanced integrity of external and cell-internal tensile forces.
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PMID:The role of matrix contact and of cell-cell interactions in choriocarcinoma cell differentiation. 882 26


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