Specific reduction of E prostaglandins to F prostaglandins and prostaglandin E 2 to prostaglandin E 1 .
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We studied the release of prostaglandin E (PGE), prostaglandin F (PGF) and 13,14-dihydro-15-keto-prostaglandin F (MPF) from explants of human placentas of different gestational ages and the effect of gonadotropin-releasing hormone (GnRH) on this release. The greatest basal release of PGE, PGF and MPF was in the cultures from 9- to 13-wk placentas, with the release on the second and third days of culture increasing 4- to 10-fold from that of the first day. In cultures from 15-wk to term placentas, the initial basal release (Day 1) of these prostaglandins was only slightly higher than in cultures from 6-wk placentas. In cultures from term placentas, the later increase with extended culture was absent or very small. Addition of synthetic GnRH to the cultures from 6- to 9-wk placentas effected no significant change in release of PGE, PGF or MPF. However, GnRH added to the cultures from 13-wk placentas effected a dose-related inhibition of these prostaglandins. After 15 wk, we observed a stimulation of these prostaglandins by GnRH that was as much as 50-fold; stimulation was highly significant in the cultures from 16- and 17-wk, as well as in those from the term placentas. These data demonstrate an action of GnRH on prostaglandin release and indicate that both the basal release of PGE, PGF and MPF and the response to GnRH are related to the gestational age of the placenta.
1. Granuloma was made by the subcutaneous injection of 2% carrageenin solution on the dorsum of male rats. Eight, 16, 24 and 72 h after the injection. the exudate from each rat granuloma was withdrawn and extracted for rpstaglandins. 2. Extracted prostaglandins were separated prostaglandin E and prostaglandin F group by silicic acid mini-column chromatography. Then the amount of prostaglandin E and prostaglandin F2alpha were determined by the radioimmunoassay method. 3. The levels of prostaglandin E in the granuloma exudates were 4.6 ng/ml at 8 h after the carrageenin injection, then decreased 3.6 ng/ml and to 1.1 ng/ml at 16 h and 24 h, respectively. Seventy-two h after the injection, prostaglandin E level was increased to 8.1 ng/ml. 4. The levels of prostaglandin F2alpha in the exudate were as follows: At 8 h after the carrageenin injection, the level was 9.4 ng/ml, then decreased to 1.3 ng/ml and to 0.8 ng/ml at 16 h and 24 h, respectively. Seventy-two h after the carrageenin injection, it was again elevated to 4.7 ng/ml. 5. The exudate of granuloma, 24 and 72 h after the carrageenin injection, was incubated with [3H]prostaglandin E1 at 37 degrees C for 30 min. Then the acidic ether extract was subjected to reversed phase partition chromatography. It was found that the exudate of 24 h and 72 h granuloma had little activity of prostaglandin 15alpha-hydroxy dehydrogenase.
Prostaglandin E (PGE) has been localized via the unlabeled antibody technique in freeze-dried and ethanol-fixed cryostat sections. Discrete perivascular and stromal localization was present in the uterus prepared by the method presented, but not in classically fixed specimens. Absorption of the anti-PGE by addition of free PGE was ineffective; whereas, removal of PGE-reactive antibodies from the anti-serum was effectively accomplished with an Affigel-101-PGE immunoadsorbant column.
We have previously shown that ovine uninucleate trophoblast cells maintained in serum-free medium on Matrigel-coated filters in dual-compartment culture chambers retain morphological polarity similar to that found in vivo. The present study was undertaken to determine the time course of tight junction formation between these cells in vitro and to characterize their basal release of prostaglandin E and F2 alpha. Trophoblast cells were purified from ovine placentomes obtained at 117-124 days of gestation and maintained in culture for up to 10 days. On each day of culture, the permeability of the cell monolayers to 3H-inulin and the secretion of prostaglandin E and F2 alpha were determined. Minimum permeability of the cell monolayers was reached by day 4 of culture, indicating that tight junction formation was complete by this time. Following an initial decrease, prostaglandin release by the trophoblast cells stabilized on days 6 to 8 of culture. On these days, prostaglandin E was secreted in equal amounts into the apical and basal compartments of the culture chamber. There was, however, 3.5 times more prostaglandin F2 alpha secreted into the apical chamber than the basal chamber at this stage of culture. These findings confirm the functional polarity of ovine trophoblast cells in culture and demonstrate differential secretion of prostaglandin E and F2 alpha by these cells.
The expression of HLA-DR antigens by normal myeloid progenitor cells (CFU-GM) has been linked to inhibition of colony growth by prostaglandin E (PGE), while resistance to the inhibitory effects of PGE in chronic myeloid leukemia (CML) has been attributed to a lower fraction of HLA-DR+ CFU-GM in this disease. However, we have previously shown that virtually all CFU-GM in normal bone marrow (NBM) as well as CML peripheral blood express HLA-DR antigens, which raises the possibility that these surface molecules may not be the sole determinants of a progenitor cell's sensitivity to PGE. In order to evaluate the relationship between HLA-DR expression and prostaglandin inhibition, we partially purified NBM progenitor cells using fluorescence-activated cell sorting to prepare cell fractions with high and low HLA-DR antigen density. Normal progenitor cells with high DR density tended to form monocyte colonies in agar culture, whereas the low DR density fraction was enriched for granulocyte colony-forming cells. Inhibition by PGE was greatest in the high DR+ fraction and was largely restricted to monocyte progenitor cells. Inhibition of CFU-GM by PGE was less in CML than in NBM, but this decreased inhibition correlated with a significantly lower number of monocyte-CFU in CML. These data suggest that high HLA-DR antigen density may select for normal progenitor cells that are committed to monocyte differentiation and are, therefore, more likely to be inhibited by PGE. The relative deficit of monocyte progenitor cells in CML may partially explain the phenomenon of PGE resistance in this disease.
PURPOSE: To evaluate the effect of tetramethylpyrazine on the elevation of aqueous flare and intraocular pressure (IOP) induced by prostaglandin (PG) E(2) and PGE(2) receptor (EP) agonists. METHODS: PGE(2) or EP agonists (11-deoxy PGE(1), EP(2) agonist; 17-phenyl trinor PGE(2), EP(1) and EP(3) agonist; or sulprostone, EP(1) and EP(3) agonist), 25 microg/mL, were transcorneally administered to pigmented rabbits. Animals were pretreated with tetramethylpyrazine intravenously (10 or 30 mg/kg) or topically (0.1% solution). Aqueous flare was measured using a laser flare-cell meter, and the intensity was expressed as the area under the curve (AUC). Intraocular pressure was measured using a noncontact tonometer. RESULTS: After administration of PGE(2), aqueous flare and IOP increased and then gradually decreased. The AUC of eyes pretreated with tetramethylpyrazine, 10 or 30 mg/kg, intravenously, or topical 0.1% solution, was significantly smaller than that of the controls. The mean Delta IOP of eyes pretreated with tetramethylpyrazine, 30 mg/kg intravenously, was significantly lower than that of the controls. After administration of 11-deoxy PGE(1), aqueous flare increased and then gradually decreased. 17-phenyl trinor PGE(2) and sulprostone did not disrupt the blood-aqueous barrier. The AUC of eyes pretreated with tetramethylpyrazine, 10 or 30 mg/kg, intravenously, before 11-deoxy PGE(1) application was significantly smaller than that of the controls. CONCLUSION: The results indicated that tetramethylpyrazine inhibited PGE(2)- or 11-deoxy PGE(1)-induced elevation of aqueous flare and IOP.
Elevated tumor cyclooxygenase-2 (COX-2) expression is associated with tumor invasion, metastasis, and poor prognosis in non-small cell lung cancer (NSCLC). Here, we report that COX-2-dependent pathways contribute to the modulation of E-cadherin expression in NSCLC. First, whereas genetically modified COX-2-sense (COX-2-S) NSCLC cells expressed low E-cadherin and showed diminished capacity for cellular aggregation, genetic or pharmacologic inhibition of tumor COX-2 led to increased E-cadherin expression and resulted in augmented homotypic cellular aggregation among NSCLC cells in vitro. An inverse relationship between COX-2 and E-cadherin was shown in situ by double immunohistochemical staining of human lung adenocarcinoma tissue sections. Second, treatment of NSCLC cells with exogenous prostaglandin E(2) (PGE(2)) significantly decreased the expression of E-cadherin, whereas treatment of COX-2-S cells with celecoxib (1 mumol/L) led to increased E-cadherin expression. Third, the transcriptional suppressors of E-cadherin, ZEB1 and Snail, were up-regulated in COX-2-S cells or PGE(2)-treated NSCLC cells but decreased in COX-2-antisense cells. PGE(2) exposure led to enhanced ZEB1 and Snail binding at the chromatin level as determined by chromatin immunoprecipitation assays. Small interfering RNA-mediated knockdown of ZEB1 or Snail interrupted the capacity of PGE(2) to down-regulate E-cadherin. Fourth, an inverse relationship between E-cadherin and ZEB1 and a direct relationship between COX-2 and ZEB1 were shown by immunohistochemical staining of human lung adenocarcinoma tissue sections. These findings indicate that PGE(2), in autocrine or paracrine fashion, modulates transcriptional repressors of E-cadherin and thereby regulates COX-2-dependent E-cadherin expression in NSCLC. Thus, blocking PGE(2) production or activity may contribute to both prevention and treatment of NSCLC.
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Albumin catalyzes the transformation of prostaglandin D2 to 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 and to isomeric prostaglandin D2 compounds including delta 12(E)-prostaglandin D2. Both of these compounds are alpha,beta-unsaturated ketones, which should render them susceptible to nucleophilic addition. We therefore examined the ability of the compounds to form conjugates with thiols glutathione and cysteine. During incubation with excess glutathione, both 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 and delta 12(E)-prostaglandin D2 formed a conjugate. Conjugation of 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 occurred very rapidly; approximately 70% was conjugated within 2 min. In contrast, conjugation of delta 12(E)-prostaglandin D2 with glutathione proceeded at a much slower rate; only 38% was conjugated at 60 min. The formation of both conjugates was enhanced by glutathione S-transferase. Conjugation of both compounds with cysteine was found to occur more rapidly than with glutathione. This effect was more pronounced with delta 12(E)-prostaglandin D2 in which 60% conjugated with cysteine within 2 min. These differences are likely attributed to greater steric hindrance for conjugation across the delta 12 double bond compared to that across the delta 9 bond. Analysis by fast atom bombardment mass spectrometry confirmed the formation of the glutathione conjugate of 9-deoxy-delta 9,delta 12(E)-prostaglandin D2. Following prolonged incubation of 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 with excess glutathione in the presence of glutathione S-transferase, a small quantity of a bis conjugate of this compound was also detected by mass spectrometry.(ABSTRACT TRUNCATED AT 250 WORDS)
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BACKGROUND AND OBJECTIVE: Prostaglandin E2 (PGE(2), a product of the cyclooxygenase 2 (COX-2) and membrane-associated Prostaglandin E Synthase (mPGES-1) pathway, has been implicated in the instability of atherosclerotic plaques. We have studied COX-2, mPGES-1 and PGE2 receptors (EPs) expression in peripheral blood mononuclear cells (PBMC) and atherosclerotic plaques of 29 patients with carotid stenosis as well as the effect of different nuclear factor-kappaB (NF-kappaB) inhibitors on COX-2, mPGES-1 and EPs expression in cultured monocytic cells (THP-1). METHODS: COX-2, mPGES-1 and EP expression was analyzed by RT-PCR (PBMC), immunohistochemistry (plaques) and Western blot (THP-1). PGE2 levels were determined by ELISA (plasma and cell supernatants). RESULTS: In relation to healthy controls, COX-2, mPGES-1 and EP-3/EP-4 mRNA expression was increased in PBMC from patients. In the inflammatory region of atherosclerotic plaques, an increase of COX-2, mPGES-1 and EPs expression was also observed. Activated NF-kappaB and COX-2, mPGES-1 and EPs proteins were colocalized in the plaque's cells. In cytokine-treated cultured THP-1, the NF-kappaB inhibitors parthenolide, Bay 11-7082 and PDTC reduced COX-2, mPGES-1 and EP-1/EP-3/EP-4 expression as well as PGE2 levels. By employing specific agonists and antagonists, we noted that the cytokine- and PGE2-induced metalloproteinase 9 (MMP-9) expression and activity occurs through EP-1/EP-3/EP-4, an effect downregulated by NF-kappaB inhibitors. CONCLUSIONS: Patients with carotid atherosclerosis depict an overexpression of COX-2, mPGES-1 and EPs simultaneously in the PBMC as well as in the vulnerable region of plaques. The studies in cultured monocytic cells suggest that NF-kappaB inhibitors and/or EPs antagonists could represent a novel therapeutic approach to the treatment of plaque instability and rupture.
Prostaglandin (PG) E and 19-OH PGE, now considered to be the most important of the human seminal prostaglandins, were assayed in infertile and normal men. In the 15 volunteers PGE and 19-OH PGE levels were 23-89 microgram/ml, respectively. In the 4 groups of infertile patients in whom either PGE or 19-OH PGE levels were increased or decreased with respect to normal, sperm concentration and motility were significantly reduced. The negative effects of low levels of seminal prostaglandins on sperm concentration and motility might be correlated respectively with decreased adenylcyclase and testicular androgen activity. The negative effects of high levels of prostaglandins on the seminal fluid might be due either to an inhibition in testicular DNA synthesis or to a decreased sensitivity of the receptors to high titers of prostaglandins.
Prostaglandin E2, transforming growth factor-beta, and interleukin-1 beta variably regulate the expression of cyclooxygenase 1, cyclooxygenase 2, and lysyl oxidase in IMR90, human embryo lung fibroblasts. Prostaglandin E2 at 100 nM upregulates cyclooxygenase 1 mRNA by approximately three-fold while it downregulates lysyl oxidase mRNA levels. Notably, prostaglandin E2 suppresses the enhancing effect of TGF-beta on basal levels of lysyl oxidase mRNA. These changes in steady state mRNA levels reflect transcriptional level control, at least in part. Corresponding changes are seen in the protein levels of lysyl oxidase, cyclooxygenase 1 and cyclooxygenase 2 and catalytic activities of these enzymes, including net prostaglandin E2 synthesis. Cyclooxygenase 2 mRNA(t1/2, 30 min) is considerably less stable than that of cyclooxygenase 1 (t1/2, 4 h) while lysyl oxidase mRNA is unusually stable (t1/2 > 14 h). Taken together with the differing kinetics with which these genes respond to perturbation by these cytokines, the present results suggest a coordinated, autocrine-like mechanism of regulation of cyclooxygenase 1 and cyclooxygenase 2 and further point to the potential of their metabolic product, prostaglandin E2, to suppress the expression of lysyl oxidase in the inflammatory response to injury.
Two experiments were conducted to determine the luteotropin of pregnancy in sheep and to examine autocrine and paracrine roles of progesterone and estradiol-17 beta on progesterone secretion by the ovine corpus luteum (CL). Secretion of progesterone per unit mass by day-8 or day-11 CL of the estrous cycle was similar to day-90 CL of pregnancy (P > or = 0.05). In experiment 1, secretion of progesterone in vitro by slices of CL from ewes on day-8 of the estrous cycle was increased (P < or = 0.05) by LH or PGE2. Secretion of progesterone in vitro by CL slices from day-90 pregnant ewes was not affected by LH (P > or = 0.05) while PGE2 increased (P < or = 0.05) secretion of progesterone. Day 8 ovine CL of the estrous cycle did not secrete (P > or = 0.05) detectable quantities of PGF2alpha or PGE while day-90 ovine CL of pregnancy secreted PGE (P < or = 0.05) but not PGF2alpha. Secretion of progesterone and PGE in vitro by day-90 CL of pregnancy was decreased (P < or = 0.05) by indomethacin. The addition of PGE2, but not LH, in combination with indomethacin overcame the decreases in progesterone by indomethacin (P < or = 0.05). In experiment 2, secretion of progesterone in vitro by day-11 CL of the estrous cycle was increased at 4-h (P < or = 0.05) in the absence of treatments. Both day-11 CL of the estrous cycle and day-90 CL of pregnancy secreted detectable quantities of PGE and PGF2alpha (P < or = 0.05). In experiment 1, PGF2alpha secretion by day-8 CL of the estrous cycle and day-90 ovine CL of pregnancy was undetectable, but was detectable in experiment 2 by day-90 CL. Day 90 ovine CL of pregnancy also secreted more PGE than day-11 CL of the estrous cycle (P < or = 0.05), whereas day-8 CL of the estrous cycle did not secrete detectable quantities of PGE (P > or = 0.05). Trilostane, mifepristone, or MER-25 did not affect secretion of progesterone, PGE, or PGF2alpha by day- 11 CL of the estrous cycle or day-90 CL of pregnancy (P > or = 0.05). It is concluded that PGE2, not LH, is the luteotropin at day-90 of pregnancy in sheep and that progesterone does not modify the response to luteotropins. Thus, we found no evidence for an autocrine or paracrine role for progesterone or estradiol-17 36 on luteal secretion of progesterone, PGE or PGF2alpha.
Prostaglandin E (PGE), a cyclooxygenase metabolite normally present in high concentrations in respiratory epithelial lining fluid (ELF), is capable of suppressing mesenchymal cell proliferation mediated by polypeptide-derived growth factors. Although PGE is normally abundant in respiratory ELF, PGE levels in ELF of individuals with idiopathic pulmonary fibrosis (IPF), a fibrotic lung disorder characterized by intraalveolar mesenchymal cell accumulation and fibrosis, were found to be 50% lower than normal (p less than 0.01): that is, a relative PGE "deficiency" in ELF may enhance intraalveolar mesenchymal cell proliferation in IPF. With this background, it is rational to consider augmenting PGE levels in ELF as a future therapy for IPF. Since systemic administration of PGE is associated with significant adverse effects, in vitro and experimental animal studies were carried out to evaluate whether aerosol PGE administration could augment ELF PGE levels. Greater than 50% of a solution of PGE1 could be placed in droplets less than 3 microns mass median aerodynamic diameter without loss of function. Aerosolization of PGE1 to sheep (n = 14) resulted in a marked augmentation of ELF PGE1 levels (preaerosol 20 +/- 7 nM, 30 min postaerosol 1,150 +/- 210 nM; p less than 0.0 to 0.1). ELF PGE1 levels remained elevated for up to 2 h (p less than 0.05 compared with baseline) and returned to baseline by 3 h (p greater than 0.2). Lung interstitial fluid (lymph) PGE1 levels increased slightly, but to levels far less than ELF levels (preaerosol 7 +/- 1 nM, 30 min postaerosol 13 +/- 2 nM; p less than 0.01), and plasma PGE1 levels did not change (p greater than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)
There was studied prostaglandins E concentration in bioptats of gastric mucosa in 158 patients with various forms and localization of chronic gastritis using a radioimmunological method. Chronic gastritis without atrophy and with mild atrophy showed to have decreased levels of prostaglandins E in comparison with the control. In the patients with atrophic gastritis with "reconstruction" of epithelium there was revealed an increase of prostaglandins concentration, which was maximal in the patients with atrophic-hyperplastic forms of the disease.
Measurement of 7alpha-hydroxy-5,11-diketotetranoprostane-1,16-dioic acid, (PGE-M), the major urinary metabolite of prostaglandin E1 and E2 in man provides a useful indicator to monitor prostaglandin biosynthesis. For quantitative analysis of this prostaglandin metabolite and the stable-isotope dilution techniqe of selected ion monitoring (SIM) is employed using gas-liquid chromatography-mass spectrometry. The preparation of the bis(D3-methyloxime), bis-methyl ester of PGE-M containing a tritium tracer in position 2 which was used as internal standard for the SIM method is described. The synthesis of this internal standard includes the biosynthetic conversion of 11-hydroxy-9,15-diketoprostanoic acid to PGE-M by the rabbit. The intra-assay coefficient of variation of this SIM method ranged between 4.0 to 6.7 percent. The recovery of authentic, underivatized PGE-M added to urine was 93 +/- 3% (mean +/- SEM, n=17). The levels of PGE-M excreted in urine were higher (p less than 0.001) in males than in females (15.2 +/- 1.9 mug/24 hours (n=24) and 3.3 +/- 0.3 mug/24 hours (n=17), respectively. These levels were in close agreement with values published previously. No significant difference in excretion of PGE-M between the sexes was observed in the pre-pubertal age-grou (male: 2.9 +/- 0.8 mug/24 hours, n=5; female: 3.1 +/- 0.9 mug/24 hours, n=5) or in the age-group of 45-80 years (male: 9.3 +/- 1.1 mug/24 hours, n=21; female: 7.3 +/- 0.9 mug/24 hours, n=12). The amount of PGE-M excreted decreased significantly after administration of indomethacin or acetyl salicylic acid in therapeutic doses. The concomitant reduction of the urinary excretion of PGE-M (68 to 85% decrease) and prostaglandin E (73 to 100% decrease) after indomethacin treatment in each case (n=8) is evidence that a diminished urinary PGE-M output reflects a decrease in prostaglandin E biosynthesis.