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PubMed1992

Regulation of GTP biosynthesis.

In the regulation of GTP biosynthesis, complex interactions are observed. A major factor is the behavior of the activity of IMPDH, the rate-limiting enzyme of de novo GTP biosynthesis, and the activity of GPRT, the salvage enzyme of guanylate production. The activities of GMP synthase, GMP kinase and nucleoside-diphosphate kinase are also relevant. In neoplastic transformation, the activities and amounts of all these biosynthetic enzymes are elevated as shown by kinetic assays and by immunotitration for IMPDH. In cancer cells, the up-regulation of guanylate biosynthesis is amplified by the concurrent decrease in activities of the catabolic enzymes, nucleotidase, nucleoside phosphorylase, and the rate-limiting purine catabolic enzyme, xanthine oxidase. The up-regulation of the capacity for GTP biosynthesis is also manifested in the stepped-up capacity of the overall pathways of de novo and salvage guanylate production. The linking with neoplasia is also seen in the elevation of the activities of IMPDH and GMP synthase and de novo and salvage pathways as the proliferative program is expressed as cancer cells enter log phase in tissue culture. The activity of GMP reductase showed no linkage with neoplastic or normal cell proliferation; however, in induced differentiation in HL-60 cells the activity increased concurrently with the decline in the activity of IMPDH. This reciprocal regulation of the two enzymes is observed in differentiation induced by retinoic acid, DMSO or TPA in HL-60 cells. In support of enzyme-pattern-targeted chemotherapy, evidence was provided for synergistic chemotherapy with tiazofurin (inhibitor of IMPDH) and hypoxanthine (competitive inhibitor of GPRT and guanine salvage activity) in patients and in tissue culture cell lines. These investigations should contribute to the clarification of the controlling factors of GMP biosynthesis, the role of the various enzymes, the behavior of GMP reductase in mammalian cells and the application of the approaches of enzyme-pattern-targeted chemotherapy in patients.

Animals↗

PubMed1979

Effects of inhibitors of steroid biosynthesis on prostaglandin formation in rabbit ovarian follicles.

Rabbit ovarian follicles were incubated without stimulation, with LH and with LH + an inhibitor or steroid biosynthesis. Formation of prostaglandins PGE and PGF and of progesterone and estradiol was measured in these incubates. It was found that aminoglutethimide phosphate (AGP) inhibited the LH stimulated biosynthesis of both prostaglandins and steroids. However U 30870 and Metyrapone, while completely inhibiting the LH stimulated biosynthesis of progesterone and estradiol respectively, had no effect on the formation of prostaglandins. Further, the inhibition of prostaglandin formation by AGP could not be reversed by exogenou steroids. It, therefore, appears that the effect of AGP on prostaglandin biosynthesis may not be related to its effect on steroid biosynthesis. However, the response of rabbit follicles to AGP is contrary to that reported for rat follicles and indicates different control mechanisms for prostaglandin formation in the follicles of the two species.

Aminoglutethimide↗

PubMed1988

Calcium requirements for barium stimulation of enkephalin and vasoactive intestinal peptide biosynthesis in adrenomedullary chromaffin cells.

The divalent cation barium was used to study the role of calcium in coupling neuropeptide secretion and biosynthesis following secretagogue stimulation of bovine chromaffin cells. Barium chloride (0.1-2.5 mM) stimulated in a dose-dependent manner the secretion of met-enkephalin (up to 20% of intracellular peptide content) and increased the total amount (cell plus medium content) of met-enkephalin and vasoactive intestinal polypeptide (VIP) 2- to 3-fold after 72 hours. A greater than six-fold increase in proenkephalin mRNA (mRNA(enk)) was observed by 24 hours following barium stimulation. The voltage-sensitive calcium channel blocker D600 inhibited the barium-stimulated secretion of enkephalin and blocked the stimulation of VIP biosynthesis and mRNA(enk). Reducing calcium in the medium resulted in an enhancement of barium-stimulated release of both peptides, but blocked the induction of their biosynthesis. The data indicate that calcium targets involved in secretion can be activated by barium or calcium while calcium targets involved in biosynthesis specifically require calcium. It is therefore proposed that pathways leading to peptide secretion and biosynthesis in the adrenal diverge just after secretagogue-stimulated calcium influx.

Adrenal Medulla↗

PubMed1995

Feeding the mosquito Aedes aegypti with TMOF and its analogs; effect on trypsin biosynthesis and egg development.

Female Aedes aegypti that were given a blood meal by enema deposited yolk in their oocytes and synthesized trypsinlike enzymes in their midgut. When females were given an enema of Aea-TMOF (Trypsin Modulating Oostatic Factor) (NH2-YDPAPPPPPP-COOH) and blood both egg development and trypsin biosynthesis were inhibited. Similar results were observed if TMOF was mixed with the blood meal and fed to female mosquitoes through a membrane. Renin inhibitor (NH2-PHPFHFFVYK-COOH) or poly proline given by enema with the blood meal did not affect egg development or trypsin biosynthesis. Feeding of TMOF analogs P1 (NH2-YDPAP-COOH) or P4 (NH2-YDPAPPPP-COOH) inhibited trypsin biosynthesis in the midgut. Injecting or giving an enema of an amidated peptide (NH2-WRPGPPPPPP-CONH2) of HIV-2 X-ORF protein also inhibited egg development and trypsin biosynthesis in the mosquito gut. When [3H]TMOF was purified by high performance liquid chromatography (HPLC) and fed with the blood meal through a membrane to female mosquitoes, [3H]TMOF outside the gut increased linearly for the first 24 h and 28% of the hormone was found outside the gut at 72 h. These results suggest that TMOF and its active analogs traverse the gut epithelial cells into the hemolymph, bind TMOF gut receptor(s) and modulate trypsin biosynthesis.

Aedes↗

PubMed1993

Effects of chlorpromazine on phosphatidylserine biosynthesis in rat pup brain exposed to ethanol in utero.

Phosphatidylserine biosynthesis in rat pup brain was examined by assaying the serine base-exchange enzyme activity in the microsomal and plasma membrane fractions, and by measuring the incorporation of [3H]serine into phosphatidylserine in brain slices and in the intact brain. Chlorpromazine, either added in vitro into the incubation system or administered to animals via i.p. injection or feeding a liquid diet, gave rise to an increase in the phosphatidylserine biosynthesis activity. Ethanol administered in the form of a liquid diet to pregnant rats (day 11 birth) resulted in a decrease in phosphatidylserine biosynthesis in the newborn and developing brain. The ethanol-induced decrease in phosphatidylserine biosynthetic activity could be reversed by adding chlorpromazine to the ethanol diet. Results demonstrate that phosphatidylserine biosynthesis in the neonatal brain is affected in opposite directions by chlorpromazine and ethanol. This poses the possibility that chlorpromazine administration may be effective in alleviating the deleterious effects caused by the decreased phosphatidylserine biosynthesis in brain due to in utero ethanol exposure.

Animals↗

PubMed1975

Restoration of nucleic acid biosynthesis after clinical death and factors stimulating the process in vivo.

The biosynthesis of RNA and DNA falls almost to zero in 60 min after the death of rabbits from anoxia, in all the organs of the body. Rapid artificial cooling of the rabbits to 20 degrees C undertaken within 10 min after death preserved nucleic acid biosynthesis and permitted restoration of life 3-4 h after death, with recovery beginning in 60 min. During the reanimation the addition of ATP to the blood stimulated the restoration of RNA biosynthesis in the spinal cord to a considerable extent; the addition of cocarboxylase to the blood promoted cardiac RNA biosynthesis as well as cardiac and pancreatic DNA biosynthesis during recovery.

Adenosine Triphosphate↗

PubMed1992

Hemosomegenesis and hemoglobin biosynthesis in vertebrates.

1. Ultrastructural observations on maturing rabbit embryo erythroid cells led to the finding of hemoglobinized organelles distinguishable from mitochondria due to their highly dense matrix, two or three longitudinally arranged double lamellae, and smaller diameters. Intraorganellar 50-60 A particles identical to those contained in the hemoglobinized cytoplasm were found. 2. Their hemoglobin (Hb) content was demonstrated by electrophoresis of the concentrated supernatant from the isolated, washed, and osmotically lysed organellar fraction. We have proposed that these organelles are the sites for heme integration into the globin (G) polypeptide chains and subunits assembly. The term hemosome has been suggested for such entities. 3. This hypothesis has been sustained by several analytical and experimental works based on the postulation that hemosomes should be found at higher frequencies where the Hb biosynthesis rate is more intensive, or where the induction of this biosynthesis is always dependent on the formation of hemosomes. 4. Maturing erythroid cells of the circulating embryo blood contain hemosomes in higher frequency than in liver erythroid cells, coinciding with the higher Hb biosynthesis rate in peripheral blood than in the liver. In bleeding anemia, the decay of Hb concentration parallels the reduction of the mean number of hemosomes per reticulocyte, in comparison with normal reticulocytes. 5. In HeLa cells and epithelial cultured cells induced to synthesize Hb, it was shown that this biosynthesis is ever concomitant with the formation of hemosomes and depends on the presence of erythropoietin, as occurs in erythroid cells. 6. Studies on hemosomegenesis and Hb biosynthesis experimentally effected in epithelial cultured cells, allowed the interpretation of the sequence of events leading to hemosome formation in maturing erythroid cells. Simultaneously with iron uptake, mitochondria differentiate to lamellated bodies and, successively, expansions rise for ferruginous compounds and G polypeptides gathering, followed by prehemosome vesicles formation, which condense and change to prohemosomes that afterwards evolve to hemosomes. 7. These dynamics, and organellar Hb have been detected in immature erythrocytes of mammalians, including humans, avians, reptilians, amphibians and representative fish specimens. It appears that these events occur in the erythrocytary maturation of all vertebrate classes.

Animals↗

PubMed1976

Amino acids as repressors of nitrogenase biosynthesis in Klebsiella pneumoniae.

Nitrogenase biosynthesis in Klebsiella pneumoniae including mutant strains, which produce nitrogenase in the presence of NH+4 (Shanmugam, K.T., Chan, Irene, and Morandi, C. (1975) Biochim. Biophys. Acta 408, 101--111) is repressed by a mixture of L-amino acids. Biochemical analysis shows that glutamine synthetase activity in strains SK-24, SK-28, and SK-29 is also repressed by amino acids, with no detectable effect on glutamate dehydrogenase. Among the various amino acids, L-glutamine in combination with L-aspartate was found to repress nitrogenase biosynthesis completely. In the presence of high concentrations of glutamine (1 mg/ml) even NH+4 repressed nitrogenase biosynthesis in the strains SK-27, SK-37, SK-55 and SK-56. Under these conditions, increased glutamate dehydrogenase activity was also detected. Physiological studies show that nitrogenase derepressed strains are unable to utilize NH+4 as sole source of nitrogen for biosynthesis of glutamate for biosynthesis of glutamate, whereas back mutations leading to NH+4 utilization results in sensitivity to repression by NH+4. These findings suggest that amino acids play an important role as regulators of nitrogen fixation.

Amino Acids↗

PubMed1976

Stimulaiton of insulin biosynthesis in isolated mouse islets by L-leucine, 2-aminonorbornane-2-carboxylic acid and alpha-ketoisocaproic acid.

An immune binding technique was used for measuring the effects of certain amino acids on the rate of insulin biosynthesis. [13H]phenylalanine served as the radioactive precursor for insulin synthesized by isolated mouse pancreatic islets. L-Leucine was found to stimulate the insulin biosynthesis and this effect was observed already at a physiologic concentration in contrast to the much higher concentrations needed to stimulate insulin secretion in vitro. Furthermore, it was found that 2-aminonorbornane-2-carboxylic acid and alpha-ketoisocaproic acid shared with glucose and L-leucine the ability to stimulate insulin biosynthesis. In contrast, L-alanine, L-arginine adn D-leucine had no stimulatory effect in the absence of glucose, while in the presence of 5 mM glucose L-arginine decreased and L-alanine increased the incorporation rate of tritiated phenylalanine. The fact that many of those compounds which stimulated insulin biosynthesis have also been shown elsewhere to be metabolized by the B-cells supports the view that the rate of insulin biosynthesis may be substrate dependent.

Amino Acids↗

PubMed1991

Biosynthetic studies of marine lipids. 35. The demonstration of de novo sterol biosynthesis in sponges using radiolabeled isoprenoid precursors.

1. De novo sterol biosynthesis in the sponges Tethya aurantia and Aplysina fistularis was investigated, using sodium [5,5-3H]-mevalonate, [1-3H]-farnesol and [3-3H]-squalene. [3-3H]-Squalene was found to be the best precursor for demonstrating de novo sterol biosynthesis in a wider range of sponges. 2. By feeding [3-3H]-squalene and using cell-free techniques, the de novo sterol biosynthesis was established in 18 sponges belonging to nine orders. Among these sponges were Axinella polypoides and Axinella verrucosa which had previously been thought to be incapable of de novo sterol biosynthesis based on work with radiolabeled lanosterol, cycloartenol, mevalonate, and acetate. 3. In contrast to earlier assumptions, it is likely that all sponges are capable of de novo sterol biosynthesis.

Animals↗

PubMed1992

Molecular genetic analysis of proline and tryptophan biosynthesis in Streptomyces coelicolor A3(2): interaction between primary and secondary metabolism--a review.

We studied the control of proline metabolism and tryptophan biosynthesis in Streptomyces coelicolor A3(2), because proline is involved in secondary metabolism [undecylprodigiosin (Red) biosynthesis] whilst tryptophan, to our knowledge, is not. Proline transport was constitutive in wild-type cells, as were the enzymes of proline catabolism. When we analysed proline biosynthesis, we discovered that growth in the presence of proline stimulated rather than repressed the biosynthetic genes. We isolated proline transport mutants and to our surprise discovered that such strains overproduced Red. As well as losing the ability to transport proline, they had lost, to differing extents, the ability to degrade proline. However, proline biosynthesis appeared to be unaffected. It appears that proline anabolism and catabolism in S. coelicolor A3(2) is in a state of dynamic equilibrium and that if this balance is disturbed, Red biosynthesis can act as a sink for excess proline. We cloned the trpD and the trpCBA clusters of S. coelicolor A3(2) and identified a promoter within the latter cluster. This promoter appeared not to be regulated by the presence or absence of exogenous tryptophan, but rather by the growth phase and/or the growth rate of the culture. It appears, therefore, that an amino acid biosynthetic pathway that is apparently not involved in secondary metabolism in the streptomycete is regulated at the genetic level--not by feedback repression, but rather by the overall physiological state of the cell.

Proline↗

PubMed1994

Effect of etodolac on prostaglandin E2 biosynthesis, active oxygen generation and bradykinin formation.

The inhibitory actions of etodolac on prostaglandin (PG) E2 biosynthesis, active oxygen generation and bradykinin formation were compared with those of indomethacin, diclofenac Na, piroxicam, naproxen, ketoprofen and aspirin. The inhibitory action (IC50 5.35 x 10(-8) M) of etodolac on PGE2 biosynthesis in rabbit articular chondrocytes stimulated by interleukin-1 (IL-1) beta was about 1/5 that of indomethacin. The inhibitory action of etodolac on spontaneous PGE2 biosynthesis in rabbit gastric epithelial cells (RGEs) (IC50 2.27 x 10(-5) M) and Madin-Darby canine kidney cells (MDCKs) (IC50 4.54 x 10(-7) M) was much less than that in rabbit articular chondrocytes stimulated by IL-1 beta and about 1/19 and 1/9 that of indomethacin in rabbit gastric epithelial cells (RGEs) and Madin-Darby canine kidney cells (MDCKs), respectively. The inhibitory action of etodolac on active oxygen generation was similar to that of indomethacin and piroxicam, and more potent than that of naproxen, ketoprofen and aspirin. The inhibitory action of etodolac on bradykinin formation was the most potent among the seven anti-inflammatory drugs tested. Both etodolac and bromelain inhibited the inflammatory pain in concanavalin A-treated paws of rats in a dose-dependent manner, but indomethacin did not. These results indicate that etodolac is an anti-inflammatory drug which suppress IL-1 beta-stimulated PGE2 biosynthesis in rabbit articular chondrocytes, active oxygen generation and bradykinin formation. It has less suppressive action against spontaneous PGE2 biosynthesis in RGEs and MDCKs. Thus, etodolac is considered to be a safe anti-inflammatory drug for clinical use.

Animals↗

PubMed1992

Evidence for a tonic inhibitory role of nifedipine-sensitive calcium channels in aldosterone biosynthesis.

This study investigated the effects of the calcium channel blockers nifedipine (a dihydropyridine) and verapamil (a papaverine derivative), on aldosterone production utilizing isolation of the early and late phases of aldosterone biosynthesis. Pregnenolone production (the early phase of aldosterone biosynthesis) was assessed in trilostane-treated bovine glomerulosa cells, used to inhibit the conversion of pregnenolone onwards to aldosterone. Conversion of exogenous corticosterone to aldosterone, an index of late phase activity, was assessed using aminoglutethimide to inhibit endogenous aldosterone production. Low concentrations of nifedipine, 10(-11)-10(-9) M, stimulated basal total aldosterone biosynthesis by enhancing the late phase although the early phase was inhibited. In the presence of 12 mM potassium (K+), which is less effective in stimulating aldosterone production than lower K+ concentrations, aldosterone production was enhanced by nifedipine, 10(-8) M, by an effect on the late phase. At K+ 6 and 8 mM, nifedipine, 10(-4) M, inhibited the early phase. Nifedipine 10(-5) inhibited angiotensin II (AII)-stimulated total aldosterone biosynthesis by independent effects on the early and late phases. Verapamil, 10(-4) M, inhibited total and early phase aldosterone production at K+, 4 mM and inhibited both phases at K+, 8 mM, stimulation was not observed using verapamil. Verapamil, 10(-4) M, also inhibited AII-stimulated aldosterone production. Basal and AII-stimulated pregnenolone production were inhibited by verapamil, 10(-4) M (basal) and 10(-6) M (AII-stimulated). These studies using nifedipine have revealed subtle calcium-dependent mechanisms involved in the tonic inhibition of activity in the late phase of aldosterone biosynthesis and the reversal of the inhibitory effect of high K+ concentrations also on the late phase. In addition, the data reported indicate that both AII and K+ independently enhance activity in the early and late phases of aldosterone production by calcium-dependent mechanisms.

Aldosterone↗

PubMed2006

Regulation of insulin biosynthesis in pancreatic beta cells by an endoplasmic reticulum-resident protein kinase IRE1.

In pancreatic beta cells, the endoplasmic reticulum (ER) is an important site for insulin biosynthesis and the folding of newly synthesized proinsulin. Here, we show that IRE1alpha, an ER-resident protein kinase, has a crucial function in insulin biosynthesis. IRE1alpha phosphorylation is coupled to insulin biosynthesis in response to transient exposure to high glucose; inactivation of IRE1alpha signaling by siRNA or inhibition of IRE1alpha phosphorylation hinders insulin biosynthesis. IRE1 activation by high glucose does not accompany XBP-1 splicing and BiP dissociation but upregulates its target genes such as WFS1. Thus, IRE1 signaling activated by transient exposure to high glucose uses a unique subset of downstream components and has a beneficial effect on pancreatic beta cells. In contrast, chronic exposure of beta cells to high glucose causes ER stress and hyperactivation of IRE1, leading to the suppression of insulin gene expression. IRE1 signaling is therefore a potential target for therapeutic regulation of insulin biosynthesis.

Animals↗

PubMed2005

Manduca sexta allatotropin and the in vitro biosynthesis of juvenile hormone by moth corpora allata: a comparison of Pseudaletia unipuncta females from two natural populations and two selected lines.

We compared the effects of Manduca sexta allatotropin (Manse-AT) on the rate of in vitro juvenile hormone (JH) biosynthesis by the corpora allata (CA) of different-aged virgin females from migrant (Quebec) and non-migrant (Azores) populations of the armyworm, Pseudaletia unipuncta, as well as from early- and late-calling lines selected from the Quebec population. There was a significant age x strain interaction, with the observed rates of JH biosynthesis in early adult life closely reflecting strain-specific differences in the age at onset of calling. In considering data for all ages combined, treatment of CA with Manse-AT resulted in a significant increase in the rate of JH biosynthesis for all but the Late strain, although significant differences for this strain were detected at certain ages. The CA of females from the Azores strain showed the strongest stimulation, with those of 0- and 1-day-old individuals displaying a singularly high degree of sensitivity. Selection for early- and late-calling lines resulted in significant differences in the temporal patterns of JH biosynthesis but did not markedly affect the sensitivity of the CA to Manse-AT. These findings are discussed within the context of the age-related differences observed in the rates of in vitro JH biosynthesis and JH haemolymph titers previously reported in comparisons of the Quebec and Azorean strains of the true armyworm.

Animal Migration↗

PubMed2005

Melanin counter act puromycin-induced inhibition of collagen and DNA biosynthesis in human skin fibroblasts.

Puromycin is an experimental anti-tumor antibiotic acting through inhibition of protein synthesis. Because of its untoward side effects (as inner ear and renal lesions) the antibiotic was not approved for clinical trials. The mechanism underlying the organ specificity of the side effect is not understood. In view of the fact that a number of drugs form with melanin complexes that affect their pharmacological activity, we determined whether puromycin interacts with melanin and how this process affects biosynthesis of collagen in cultured human skin fibroblasts. Our results indicate that puromycin forms complexes with melanin. The amount of puromycin bound to melanin increases with increase of initial drug concentration. The Scatchard plot analysis of the drug binding to melanin has shown that at least two classes of independent binding sites are implicated in the puromycin-melanin complex formation: one class of strong binding sites with the association constant K1 = 1.84 x 10(6) M(-1), and the second class of weak binding sites with the association constant K2 = 5.26 x 10(3) M(-1). The number of total binding sites were n1 = 0.1260 and n2 = 0.2861 mumol puromycin per 1 mg melanin. We found that puromycin induced inhibition of collagen and DNA biosynthesis (IC50 approximately 2 microM). Melanin at 100 microg/ml produced about 20% inhibition of DNA synthesis, but it had no effect on collagen biosynthesis in cultured fibroblasts. However, the addition of melanin (100 microg/ml) to puromycin - treated cells (2 microM) abolished the inhibitory action of puromycin on collagen and DNA biosynthesis. We have suggested that IGF-I receptor expression, involved in collagen metabolism, may be one of the targets for puromycin - induced inhibition of collagen biosynthesis. It was found that melanin abolished puromycin induced decrease in the expression of IGF-I receptor as well MAP kinases expression: ERK1 and ERK2 as shown by Western immunoblot analysis. These data suggest that tissue specific pharmacological activity of puromycin may depend on the melanin abundance in tissues.

Antimetabolites, Antineoplastic↗

PubMed2005

Upregulation of sterol C14-demethylase expression in Trypanosoma cruzi treated with sterol biosynthesis inhibitors.

Infection with the protozoan, Trypanosoma cruzi, is the cause of Chagas disease that occurs widely throughout Latin America. T. cruzi contains sterol biosynthesis enzymes, and produces sterol products similar to those found in fungi. Antifungal drugs that inhibit ergosterol biosynthesis have potent anti-T. cruzi activity in vitro and in animal models. In this report, we describe the effects of sterol biosynthesis inhibitors (simvistatin, zaragosic acid, terbinafine, a lanosterol synthase inhibitor, ketoconazole, and tridemorph) on the regulation of two sterol biosynthesis genes and their protein products. Culturing T. cruzi in the presence of the lanosterol synthase inhibitor, terbinafine, or ketoconazole increased mRNA levels of the sterol C14-demethylase gene approximately 7-12-fold. The sterol C14-demethylase protein levels were also elevated. The effects of the sterol biosynthesis inhibitors on hydroxymethylglutaryl-CoA reductase expression were minimal. Control of the upregulation of sterol C14-demethylase appears to be mediated through the 3'-untranslated region of the gene. The findings demonstrate that T. cruzi can specifically regulate gene expression in response to derangements in its cellular functions.

Animals↗

PubMed2005

Systemic inflammation induces COX-2 mediated prostaglandin D2 biosynthesis in mice spinal cord.

Although prostaglandin (PG)D2 is one of the main metabolites of the cyclooxygenase (COX) pathway of arachidonate metabolism in the brain, relatively little is known about the regulation of PGD2 biosynthesis in the spinal cord during systemic inflammation. Therefore, the present study was aimed at investigating the effect of endotoxin treatment on spinal PGD2 biosynthesis in BALB/c mice. Spinal inflammatory response to systemic endotoxin was verified by determination of spinal TNFalpha and IL-1beta mRNA. COX-1, COX-2, membrane-bound prostaglandin E synthase-1 (mPGES-1), and lipocalin-type prostaglandin D synthase (L-PGDS) mRNA and protein were determined by RT-PCR and western blot, respectively. The concentrations of immunoreactive PGD2 and PGE2 were measured in superfusion media of spinal cord samples in-vitro. Endotoxin treatment (1 mg/kg; 24 h before) enhanced the expression of COX-2, mPGES-1, and L-PGDS mRNA and protein in spinal cord, while there was no significant effect on COX-1 mRNA and protein. In superfusion media of spinal cord samples obtained from endotoxin treated mice, the concentrations of immunoreactive PGE2 and PGD2 were higher than in the control group suggesting enhanced spinal PG biosynthesis after endotoxin treatment. Addition of the selective COX-2 inhibitor lumiracoxib (100 nM) to the superfusion medium did not significantly affect PGE2 or PGD2 release in spinal cord obtained from non-treated mice. In spinal cord of endotoxin-treated mice, lumiracoxib (100 nM) attenuated PGE2 and PGD2 release to values similar to those observed in tissue obtained from non-endotoxin-treated mice. These results show enhanced expression of spinal L-PGDS and increased spinal PGD2 biosynthesis during systemic inflammation whereby enhanced biosynthesis seems to be dependent primarily on COX-2 activity.

Animals↗