6-ketoprostaglandin-f1-alpha and 5-hydroxy-6-8-11-14-eicosatetraenoic-acid

Interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF alpha) induce prostanoid biosynthesis in vascular smooth muscle cells by promoting cyclooxygenase (COX) expression, but little is known about the biosynthesis of lipoxygenase (LPO) metabolites. We investigated the effects of human recombinant IL-1beta and TNF alpha on the production of arachidonic acid (AA) metabolites by high-performance liquid chromatography (HPLC). After being labelled with 3H-AA, cultured human pulmonary artery smooth muscle cells (HPASMC) were incubated with or without IL-1beta (200 U/ml) and TNF alpha (500 U/ml). The arachidonic acid metabolites released from HPASMC were then analysed by HPLC. In control HPASMC, 6-keto-PGF1alpha and PGE2 were the principal metabolites of the COX pathway, while 5-HETE, LTC4 and D4 were the main products of the LPO pathway. HPASMC treated with 200 U/ml of IL-1beta and 500 U/ml of TNF alpha produced more COX metabolites such as 6-keto-PGF1alpha, thromboxane B2, PGF2alpha and PGE2 than control cells. Significant increases in the production of LPO derivatives such as LTB4, C4, D4, and 15-HETE were also found in IL-1beta-treated HPASMC. Although the release of LPO products tended to increase in TNF alpha-treated cells, no significant change was noted. Many AA metabolites including LTB4 are responsible for the inflammatory process in vivo. AA metabolites produced by pulmonary artery smooth muscle cells might play important roles in cytokine-mediated acute lung injury and inflammation.

Topics: 6-Ketoprostaglandin F1 alpha; Cells, Cultured; Chromatography, High Pressure Liquid; Dinoprostone; Eicosanoids; Humans; Hydroxyeicosatetraenoic Acids; Interleukin-1; Leukotriene C4; Leukotriene D4; Muscle, Smooth, Vascular; Pulmonary Artery; Tumor Necrosis Factor-alpha

The effect of tenidap on the metabolism of arachidonic acid via the 5-lipoxygenase (5-LO) pathway was investigated in vitro and in vivo.. In vitro (cells). Arachidonic acid (AA) stimulated rat basophilic leukemia, (RBL) cells; A23817 activated neutrophils (human rat, and rabbit), macrophages (rat), and blood (human). In vitro (enzyme activity). RBL-cell homogenate; purified human recombinant 5-LO. In vivo: Rat (Sprague-Dawley) models in which peritoneal leukotriene products were measured after challenge with zymosan (3 animals per group), A23187 (11 animals per group), and immune complexes (3-5 animals per group), respectively.. 5-Hydroxyeicosatetraenoic acid (5-HETE) and dihydroxyeicosatetraenoic acids (diHETEs, including LTB4) were measured as radiolabeled products (derived from [14C]-AA) or by absorbance at 235 or 280 nm, respectively, after separation by HPLC. Radiolabeled 5-HPETE was measured by a radio-TLC analyser after separation by thin layer chromatography (TLC). Deacylation of membrane bound [14C]-AA was determined by measuring radiolabel released into the extracellular medium. 5-LO translocation from cytosol to membrane was assessed by western analysis. Rat peritoneal fluid was assayed for PGE, 6-keto-PGF1 alpha, LTE4 or LTB4 content by EIA and for TXB2 by RIA.. Tenidap suppressed 5-LO mediated product production in cultured rat basophilic leukemia (RBL-1) cells from exogenously supplied AA, and in human and rat neutrophils, and rat peritoneal macrophages stimulated with A23187 (IC50, 5-15 microM). In addition, tenidap was less potent in inhibiting the release of radiolabeled AA from RBL-1 cells (IC50, 180 microM), suggesting that the decrease in 5-LO derived products could not be explained by an effect on cellular mobilization of AA (i.e., phospholipase). Tenidap blocked 5-hydroxyeicosatetraenoic acid (5-HETE) production by dissociated RBL-1 cell preparations (IC50, 7 microM), as well as by a 100000 x g supernatant of 5-LO/hydroperoxidase activity, suggesting a direct effect on the 5-LO enzyme itself. In addition, tenidap impaired 5-LO translocation from cytosol to its membrane-bound docking protein (FLAP) which occurs when human neutrophils are stimulated with calcium ionophore, indicating a second mechanism for inhibiting the 5-LO pathway. Surprisingly, tenidap did not block the binding of radiolabeled MK-0591, an indole ligand of FLAP, to neutrophil membranes. Although its ability to inhibit the cyclooxygenase pathway was readily observed in whole blood and in vivo, tenidap's 5-LO blockade could not be demonstrated by ionophore stimulated human blood, nor after oral dosing in rat models in which peritoneal leukotriene products were measured after challenge with three different stimuli. The presence of extracellular proteins greatly reduced the potency of tenidap as a 5-LO inhibitor in vitro, suggesting that protein binding is responsible for loss of activity in animal models.. Tenidap inhibits 5-lipoxygenase activity in vitro both directly and indirectly by interfering with its translocation from cytosol to the membrane compartment in neutrophils. A potential mechanism for the latter effect is discussed with reference to tenidap's ability to lower intracellular pH. Tenidap did not inhibit 5-LO pathway activity in three animal models.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Calcimycin; Chemotactic Factors; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Erythrocytes; Humans; Hydroxyeicosatetraenoic Acids; Immunoenzyme Techniques; Indoles; Ionophores; Leukemia, Basophilic, Acute; Leukotriene B4; Leukotriene E4; Lipoxygenase Inhibitors; Neutrophil Activation; Neutrophils; Oxindoles; Rabbits; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Thromboxane B2; Zymosan

To examine the effects of ropivacaine, currently being investigated for treatment of ulcerative colitis, on the release of arachidonic acid metabolites.. Human granulocytes and endothelial cells.. Ropivacaine, lidocaine, hydrocortisone, 5-aminosalicylic acid or acetylsalicylic acid (10-1000 microM).. Leukotriene B4, 5-hydroxyeicosatetraenoic acid, 6-keto PGF1 alpha and 15-hydroxyeicosatetraenoic acid were measured using immuno assays. Wilcoxon signed rank test was used for statistical calculations.. Ropivacaine dose-dependently inhibited zymosan-induced release of leukotriene B4 and 5-hydroxyeicosatetraenoic acid whereas the release after ionophore stimulation was not affected. Ropivacaine was more potent than 5-aminosalicylic acid but less potent compared to hydrocortisone. Ropivacaine had only a weak inhibitory effect on the release of 15-hydroxyeicosatetraenoic acid from zymosan- or ionophore-stimulated cells. In contrast to hydrocortisone and 5-aminosalicylic acid, ropivacaine only weakly affected the release of 6-keto PGF1 alpha after stimulation with thrombin.. The inhibited release of 5-lipoxygenase products may account for some of the anti-inflammatory effects of ropivacaine seen in the treatment of ulcerative colitis.

Topics: 6-Ketoprostaglandin F1 alpha; Amides; Anesthetics, Local; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Cells, Cultured; Eicosanoids; Endothelium, Vascular; Granulocytes; Humans; Hydrocortisone; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Lidocaine; Mesalamine; Ropivacaine; Thrombin; Zymosan

Endothelial cells actively regulate their environment by secreting humoral substances, including endothelin-1 and a variety of eicosanoids, that have local actions. To elucidate interactions among these local mediators, we measured release of cyclooxygenase and lipoxygenase pathway products of arachidonate metabolism by human aortic endothelial cells after incubation with endothelin-1. Supernatants were collected, extracted, and fractionated using high-performance liquid chromatography. Radioimmunoassays for eicosanoids were performed on the appropriate fractions. After endothelin stimulation, production of the prostacyclin metabolite 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), the thromboxane (Tx) metabolite TxB2, and prostaglandin E2 (PGE2) were increased (307 +/- 48, 320 +/- 91, and 315 +/- 74% of control, P < 0.05). Leukotriene B4 (LTB4) release was modestly increased (195 +/- 19% of control, P < 0.05). The release of 5-hydroxyeicosatetraenoic acid (5-HETE) was increased (300 +/- 57% of control, P < 0.05); production of 12-HETE and 15-HETE was unchanged. Production of eicosanoids peaked between 30 and 120 min. Preincubation with pertussis toxin prevented increased production of PGE2, LTB4, and 5-HETE after endothelin-1 stimulation; pretreatment with sphingosine had no effect. Interactions between endothelin and eicosanoids may be important components of the complex network that regulates vascular tone, coagulation, and inflammation at the local level.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 6-Ketoprostaglandin F1 alpha; Aorta; Arachidonic Acid; Cells, Cultured; Dinoprostone; Eicosanoids; Endothelins; Endothelium, Vascular; Gas Chromatography-Mass Spectrometry; Humans; Hydroxyeicosatetraenoic Acids; Kinetics; Leukotriene B4; Pertussis Toxin; Thromboxane B2; Virulence Factors, Bordetella

We evaluated the effect of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) on pig cardiopulmonary function by intravenously infusing each cytokine individually or in combination (0.5 microgram/kg from 0 to 0.5 h + 5 ng.kg-1 x min-1 from 0.5 to 6 h for each cytokine). The role of eicosanoids in mediating the TNF-alpha + IL-1 alpha-induced cardiopulmonary dysfunction was also investigated by pretreating cytokine-infused pigs with CGS 8515 (5-lipoxygenase inhibitor) or indomethacin (cyclooxygenase inhibitor). Coinfusion of TNF-alpha with IL-1 alpha caused additive increases (P < 0.05) in total peripheral resistance and plasma concentrations of 6-keto-prostaglandin F1 alpha (PGF1 alpha). The increases in mean pulmonary arterial pressure (Ppa), pulmonary vascular resistance (PVR), alveolar-arterial O2 gradient (AaDO2), alveolar dead space-to-tidal volume ratio (VD/VT), and plasma concentrations of thromboxane B2 were either additive or synergistic. CGS 8515 blocked the TNF-alpha + IL-1 alpha-induced increases (P < 0.05) in mean aortic pressure, total peripheral resistance (4-6 h), VD/VT (5-6 h), and, at 6 h, attenuated the increases in Ppa, PVR, and AaDO2. Indomethacin blocked or attenuated the cytokine-induced increases (P < 0.05) in Ppa, PVR, AaDO2, VD/VT, and plasma concentrations of thromboxane B2 and 6-keto-PGF1 alpha. The 1-to 2-h systemic hypotension, caused by TNF-alpha + IL-1 alpha, was not abrogated by either indomethacin or CGS 8515. The cytokines did not alter plasma concentrations of leukotriene B4 or 5-hydroxyeicosatetraenoic acid. We conclude that coinfusion of TNF-alpha with IL-1 alpha induces physiological responses that are additive or synergistic and that cyclooxygenase and 5-lipoxygenase products (other than leukotriene B4 and 5-hydroxyeicosatetraenoic acid) importantly mediate cardiopulmonary dysfunction in pigs infused with TNF-alpha + IL-1 alpha.

Topics: 6-Ketoprostaglandin F1 alpha; Albumins; Animals; Arachidonic Acids; Bronchoalveolar Lavage Fluid; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Cytokines; Dinoprost; Drug Synergism; Eicosanoids; Heart; Heart Diseases; Hydroxyeicosatetraenoic Acids; Indomethacin; Injections, Intravenous; Interleukin-1; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Lung Diseases; Naphthoquinones; ortho-Aminobenzoates; Swine; Thromboxane B2; Tumor Necrosis Factor-alpha; Vascular Resistance

The effects of interleukin-1 alpha (IL-1 alpha) on arachidonic acid (AA) metabolism were studied in the human osteosarcoma cell lines, G292 and SaOS-2. The cells were prelabeled with 3H-arachidonic acid. Radiolabeled metabolites were measured by reversed-phase high-pressure liquid chromatography with a radioactive detector. Indomethacin inhibited prostaglandin E2 (PGE2) production without affecting lipoxygenase (LO) products in G292 cells. In the G292 cells, IL-1 alpha (50 U/ml) induced a 10-fold increase in PGE2 production at all the incubation times tested, and a significant two-fold increase in 5 hydroxyeicosatetraenoic acid (HETE) formation after 48 h. These effects were not seen in SaOS-2 cells under identical conditions. These results suggest that, although some osteosarcomal cell lines may not respond directly to IL-1 with effects on AA metabolism, the mechanism of its action in others may involve modulation of both cyclooxygenase (CO) and LO pathways.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 6-Ketoprostaglandin F1 alpha; Arachidonic Acid; Dinoprostone; Humans; Hydroxyeicosatetraenoic Acids; Indomethacin; Interleukin-1; Leukotriene B4; Lipoxygenase; Osteoblasts; Osteosarcoma; Tumor Cells, Cultured

Cultured porcine aortic endothelial cells were conditioned through two passages to mimic euglycemic and hyperglycemic conditions (5.2 mM, normal glucose; 15.6 mM, elevated glucose). After incubation with 1 microM [14C]arachidonic acid for 24 h, the cells were stimulated with 1 microM A23187 for times up to 30 min. Uptake of [14C]arachidonic acid and its distribution among cell lipids were unaffected by the increased glucose concentration. The release of eicosanoids from labeled cells and unlabeled cells was measured by reverse-phase HPLC and by RIA, respectively. Compared with cells stimulated in the presence of normal glucose concentrations, cells stimulated in the presence of elevated glucose released 62.6% less free [14C]arachidonic acid, but released 129% more 14C-labeled 15-hydroxyeicosatetraenoic acid (HETE). Increased release of 15-HETE in the presence of elevated glucose in response to A23187, bradykinin, and thrombin was confirmed by RIA. A similar increase in 5-HETE release was observed by RIA after A23187 treatment. The release of both radiolabeled and unlabeled prostanoids was equal at both glucose concentrations. The data indicate that glucose may play an important role in the regulation of release and metabolism of arachidonic acid after agonist stimulation. In the presence of elevated glucose concentrations, such as those associated with diabetes mellitus, the extent and pattern of eicosanoid release from endothelial cells is markedly altered.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Aorta; Arachidonic Acid; Arachidonic Acids; Bradykinin; Calcimycin; Eicosanoic Acids; Endothelium, Vascular; Glucose; Hydroxyeicosatetraenoic Acids; Swine; Thrombin

Recent evidence has shown that a variety of prostaglandins and leukotrienes can be produced in brain tissue after injury in animals. It has also been speculated that increases in brain prostaglandins occur in humans following injury. Ventricular cerebrospinal fluid (CSF) samples have been obtained from children with static lesions (controls) as well as children with acute brain injury and eicosanoids measured by immunologic techniques. Metabolites of prostacyclin (6-keto-PGF1 a) and thromboxane A2 (thromboxane B2) were the major eicosanoids found in CSF, and levels of these compounds were increased 3-10 times in acutely injured patients. Prostaglandin E2 was also found in lower amounts, although in one case its level was very high. Prostaglandin D2 was also present, but in low amounts. No leukotrienes were found in CSF samples that were purified by HPLC prior to immunoassay. Elevated levels of hydroxyeicosatetraenoic acids (HETEs) were observed in those samples stored frozen, but these metabolites were most probably due to autooxidation of arachidonic acid in CSF. Arachidonic acid concentration in CSF was typically found to be in the range of 10-200 ng/ml, but was found to be 5-10 fold higher in one severely injured patient. Thus, elevated free arachidonic acid and various oxygenated metabolites were observed in CSF following brain injury.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 6-Ketoprostaglandin F1 alpha; Adolescent; Arachidonic Acid; Arachidonic Acids; Brain Injuries; Cerebral Ventricles; Child; Child, Preschool; Chromatography, High Pressure Liquid; Dinoprostone; Eicosanoic Acids; Humans; Hydroxyeicosatetraenoic Acids; Infant; Infant, Newborn; Leukotriene B4; Prostaglandin D2; Prostaglandins D; Prostaglandins E; SRS-A; Thromboxane B2

Confluent cultures of porcine aortic endothelial cells were prelabeled with 1 microM [14C]arachidonic acid complexed to 1 microM bovine serum albumin. After washing, the cells were stimulated with 1 microM A23187 for time intervals between 30 s and 30 min. Cellular lipids were extracted and separated into major lipid classes and phospholipid subclasses. The external medium was analyzed for released radioactive eicosanoids. The time-course of total release of 14C radioactivity demonstrated a biphasic nature of A23187-induced changes in endothelial cell lipids. Early, from 30 s to 5 min, substantial losses of [14C]arachidonic acid from diacylphosphatidylethanolamine and phosphatidylinositol, as well as an abrupt increase in diacylphosphatidylcholine-associated radioactivity were observed. These initial changes coincided with the release of 14C-labeled cyclooxygenase products. Later changes (5-30 min) included a sustained progressive loss of 14C radioactivity from alkenyl (alk-1-enyl) acylphosphatidylethanolamine and diacylphosphatidylcholine. These later changes coincided with the elaboration of 14C-labeled lipoxygenase products. Although unequivocal assignments cannot be made, the data suggest that specific pools of arachidonic acid provide precursors for individual classes of eicosanoids.

Topics: 6-Ketoprostaglandin F1 alpha; Acylation; Animals; Aorta, Thoracic; Arachidonic Acid; Arachidonic Acids; Calcimycin; Cells, Cultured; Endothelium, Vascular; Ethers; Fatty Acids, Unsaturated; Hydroxyeicosatetraenoic Acids; Kinetics; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylinositols; Phospholipids; Swine

Eicosanoids are known mediators of inflammation, vascular permeability, and are involved in microcirculatory blood flow regulation. To study their potential involvement in the pathophysiology of CNS trauma we used a rabbit spinal cord trauma model. Rabbits were subjected to lumbar spinal cord trauma produced by a modification of the Allen weight-drop method. TXB2, 6-keto-PGF1 alpha, PGE2, and 5-hydroxyeicosatetraenoic acid (5-HETE) release from spinal cord slices incubated ex vivo were measured by radioimmunoassay at 5, 30 min, 24 hrs, and 2 wks after trauma. Five and 30 min after trauma the TXB2/6-keto-PGF1 alpha ratio was elevated and the release of 5-HETE at 5 min after trauma increased in the injured spinal cord whereas release of 6-keto-PGF1 alpha and PGE2 remained at base-line levels. In the thoracic spinal cord, TXB2 and 6-keto-PGF1 alpha release were increased at 30 min after trauma. Release of 5-HETE from the injured spinal cord was also elevated 24 hrs after trauma. Two wks after trauma, TXB2 and 6-keto-PGF1 alpha release were also elevated in the injured spinal cord. Measurements of tissue water content by microgravimetry indicated progressive edema in the injury site while histopathological evaluation indicated progressive damage and tissue destruction. The results of this study suggest that eicosanoids may be involved in the pathophysiology of spinal cord trauma through two potential mechanisms: 1) site specific increase in the TXB2/6-keto-PGF1 alpha ratio immediately following trauma which is due primarily to an increase in TXA2 synthesis; 2) the increase synthesis of 5-HETE which signals the activation of the 5-lipoxygenase pathway of arachidonate metabolism and production of mediators that are involved in inflammatory mechanisms and may affect local blood flow regulation and blood-spinal cord barrier integrity.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Culture Techniques; Dinoprostone; Edema; Hydroxyeicosatetraenoic Acids; Male; Prostaglandins E; Rabbits; Spinal Cord; Spinal Cord Injuries; Thromboxane B2

The anti-inflammatory activity of nonsteroidal anti-inflammatory drugs is primarily attributed to inhibition of distinct steps in the arachidonic acid cascade, particularly, the cyclo-oxygenase pathway. Diclofenac sodium, a compound of this class of drugs, appears to have a dual effect since it also regulates the lipoxygenase pathway. Study of appropriate cell systems (leukocytes and whole blood in rats) demonstrates that diclofenac's potent inhibition of cyclo-oxygenase activity causes a sharp reduction in the formation of prostaglandin, prostacyclin, and thromboxane products, all key mediators of inflammation. Recent work discloses that at higher concentrations, diclofenac sodium also reduces the formation of products of the lipoxygenase pathway (5-hydroxyeicosatetraenoic acid, leukotrienes). The mechanism by which this evolves, however, appears to be unrelated to direct inhibition of lipoxygenase. Instead, by enhancing its reincorporation into triglycerides, diclofenac sodium reduces the intracellular level of free arachidonic acid.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arachidonate Lipoxygenases; Arachidonic Acid; Arachidonic Acids; Cyclooxygenase Inhibitors; Diclofenac; Dinoprostone; Humans; Hydroxyeicosatetraenoic Acids; Ibuprofen; Leukocytes; Lipoxygenase Inhibitors; Monocytes; N-Formylmethionine Leucyl-Phenylalanine; Naproxen; Phospholipids; Piroxicam; Prostaglandins E; Rats; SRS-A; Thiazines; Triglycerides

The recent availability of fast and sensitive radioimmunoassay (RIA) and enzyme immunoassay (EIA) procedures to measure icosanoids has led to utilization of these techniques by many investigators. A major concern has been that techniques based on immunoreactivity may lack specificity, in particular if complex biologic fluids or tissue extracts are evaluated. The purpose of this investigation was the comparison of icosanoid measurements obtained either with EIA or RIA with those obtained by gas chromatography/mass spectrometry (GC/MS). Rats were injected with Salmonella enteritidis endotoxin, killed at various times after the injection and the lung extract assayed for 6-keto-PGF1 alpha, 5-HETE and LTC4. By EIA lung tissue was found to contain large quantities of 6-keto-PGF1 alpha after endotoxin stimulation. Comparisons made between EIA and GC/MS analysis showed good correlation between 6-keto-PGF1 alpha amounts in lung as determined by each technique. It was also determined that little purification of lung extract was needed to obtain reliable quantitation of 6-keto-PGF1 alpha, probably due to the specificity of the antibody and the large quantity of this prostaglandin produced. Crudely purified (Sep-Pak) lung extracts gave 5-HETE levels by RIA which were highly correlated with GC/MS values, but RIA values were 70% higher than those obtained by GC/MS. The presence of other components in lung extract which cross react with this 5-HETE antibody was probably responsible for the higher values obtained by RIA. LTC4 was measured by immunoassay in crude lung extracts, as well as after Sep-Pak purification and HPLC purification. LTC4 levels were identical in unpurified lung extract and after Sep-Pak purification, but decreased substantially after HPLC purification. Thus, by validating the icosanoid immunoassays, we have found that they can give accurate and reproducible results in lung tissue, although LTC4 and 5-HETE must be purified prior to analysis.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Gas Chromatography-Mass Spectrometry; Hydroxyeicosatetraenoic Acids; Immunoenzyme Techniques; Lung; Radioimmunoassay; Rats; Rats, Inbred Strains; SRS-A

We have measured by radioimmunoassay the concentration and production of 5(S)-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), a metabolite in the lipoxygenase pathway, and PGs in different uterine compartments, and blastocysts during the preimplantation period in the rabbit. The production is defined as the synthesis minus the metabolism for a defined period of time. The pattern of uterine PGF production on days 5-6.5 was quite similar for the whole uterus and the myometrium showing a peak production on Day 6. The concentration and production of PGF were always higher in the endometrium. While significant production of PGE was noticed in the whole uterus on days 5-6 and in the myometrium on Day 6, the endometrium showed some production on these days. On the contrary, absolutely no production of this PG was observed in the endometrium on Day 6.5. The concentration and production of 6-keto-PGF1 alpha were always lower in the endometrium than those observed in the myometrium or the whole uterus. While highest production of this PG was found to be on Day 6.5 in the whole uterus and on Day 5 in the endometrium, the production in the myometrium remained constant on all days examined. The production of 5-HETE in the endometrium was noticeable on Days 5-6.5, in the whole uterus on Days 5 and 6.5, and in the myometrium only on Day 6.5. However, the concentrations of 5-HETE showed a tendency to be higher at 2 h than at 0 h in these compartments on Days 5-6.5. Furthermore, a linear increase in 5-HETE levels both at 0 h and 2 h was observed in the endometrium on Days 5-6.5; no such difference in mean 5-HETE level was noted in the whole uterus or myometrium on any of these days. The production of 5-HETE in the blastocyst was noted only on Day 5. The results not only demonstrate the presence of both the cyclooxygenase and the lipoxygenase pathways in the preimplantation rabbit uterus and blastocyst, their differential operation in various compartments of the uterus on various days of early pregnancy suggests an integrated role for these mediators in embryo-uterine interaction during implantation.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blastocyst; Embryonic Development; Female; Hydroxyeicosatetraenoic Acids; Lipoxygenase; Pregnancy; Prostaglandin-Endoperoxide Synthases; Prostaglandins E; Prostaglandins F; Rabbits; SRS-A; Uterus

Evidence has been presented that inhibition by diclofenac sodium of the production of leukotrienes by cells participating in the inflammatory process is due to a decreased availability of intracellular arachidonic acid which results from enhanced uptake of the substrate into triglyceride pools. The diminished leukotriene production does not result from direct inhibition of 5-lipoxygenase or phospholipase A2. Reduced availability of arachidonic acid would also limit production of prostaglandins, although in this case manifestation is obscured by the potent inhibitory effect of diclofenac sodium on cyclooxygenase. This recently discovered action of diclofenac sodium, which has been characterized by studies on isolated leukocytes, appears to be operative in vivo. Consistent with this mechanism, and not explainable by classical cyclooxygenase inhibition, diclofenac sodium inhibited leukotriene production in whole blood from drug-treated animals and also suppressed leukocyte infiltration of subcutaneously implanted sponges. The latter effect contrasts with increased infiltration frequently obtained with other NSAIDs and thought to reflect enhanced production of leukotrienes. In conclusion, the findings suggest that patient acceptance or preference for diclofenac sodium is not merely subjective but has a logical scientific basis.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arachidonic Acid; Arachidonic Acids; Chemotaxis, Leukocyte; Cyclooxygenase Inhibitors; Diclofenac; Dinoprostone; Humans; Hydroxyeicosatetraenoic Acids; Ibuprofen; Indomethacin; Leukocytes; Lipoxygenase; Naproxen; Phospholipases A; Phospholipases A2; Phospholipids; Piroxicam; Prostaglandins E; SRS-A; Thiazines; Triglycerides