Prostaglandins in dysfunctional labour; evidence for altered production of prostaglandin F2 alpha

1990 ◽  
Vol 2 (5) ◽  
pp. 563 ◽  
Author(s):  
RJ Norman ◽  
K Reddi
Keyword(s):  
Arachidonic Acid ◽  
Amniotic Fluid ◽  
Prostaglandin E2 ◽  
Fetal Membranes ◽  
Clinical Validation ◽  
Prostaglandin Synthetase ◽  
Prostaglandin F2 Alpha ◽  
Alpha Production ◽  
Low Concentrations

Dysfunctional labour was studied in relation to prostaglandin concentrations in amniotic fluid and production by fetal membranes. Initial clinical validation of the model established the presence of hypokinetic labour with no evidence of obstruction to the fetal progress. Prostaglandin F2 alpha (PGF2 alpha) and 13, 14 dihydro-15-keto-prostaglandin-F2 alpha concentrations in the amniotic fluid were low despite relatively normal concentrations of prostaglandin E2. Membranes removed from patients with the condition released very low concentrations of PGF2 alpha from the amniotic side with no alteration on the choriodecidual side of the membrane. Studies of free and phospholipid-associated arachidonic acid indicated normal release of arachidonic acid in dysfunctional labour. No changes in amniotic fluid-related inhibitors and stimulators of prostaglandin synthetase were detected. It is suggested that PGF2 alpha production is impaired in dysfunctional labour and that this prostaglandin is primarily involved in the progress of labour.

scholarly journals Phospholipase A activity in the skin. Modulators of arachidonic acid release from phosphatidylcholine

1979 ◽  
Vol 184 (2) ◽  
pp. 283-290 ◽  
Author(s):  
V A Ziboh ◽  
J T Lord
Keyword(s):  
Arachidonic Acid ◽  
Prostaglandin E2 ◽  
Specific Activity ◽  
Feedback Regulation ◽  
Phospholipase A ◽  
Particulate Fraction ◽  
Prostaglandin F2 Alpha ◽  
Low Concentrations ◽  
Freeze Dried ◽  
Hydrolysis Of

The distribution of the hydrolysis of 1-acyl-2-[1-14C]arachidonoyl-sn-glycero-3-phosphocholine and the simultaneous biosynthesis of prostaglandins by subcellular fractions from human and rat skin membrane preparations were determined. The phospholipase A2 activity was distributed among the subcellular particulate preparations with the highest specific activity in the 105000g particulate fraction. The activity was optimal at pH 7.5 in the presence of 1.0 mM-CaCl2 and was inhibited by EDTA. The hydrolysis of phosphatidylcholine by the skin 105000g particulate fraction was inhibited by cortisol and triamcinolone acetonide and it was stimulated by histamine, bradykinin, retinoic acid and cholera enterotoxin (freeze-dried Vibrio cholerae). Furthermore hydrolysis of phosphatidylcholine by the skin phospholipase A was also enhanced by low concentrations of prostaglandin E2 and prostaglandin F2 alpha. These last results suggest that the amplication of the hydrolysis of phosphatidylcholine by prostaglandin E2 and prostaglandin F2 alpha, with the consequent release of arachidonic acid (the substrate of prostaglandin synthesis) is likely a positive-feedback regulation of the arachidonic acid-prostaglandin cascade.

Endothelium-dependent contractions to arachidonic acid are mediated by products of cyclooxygenase

1985 ◽  
Vol 248 (4) ◽  
pp. H432-H437 ◽  
Author(s):  
V. M. Miller ◽  
P. M. Vanhoutte
Keyword(s):  
Arachidonic Acid ◽  
Prostaglandin E2 ◽  
Isometric Tension ◽  
Optimum Length ◽  
Prostaglandin F2 Alpha ◽  
Thromboxane Synthetase ◽  
High Concentrations ◽  
Endothelium Dependent Relaxation ◽  
By Products

Arachidonic acid produces endothelium-dependent relaxation in canine arteries and endothelium-dependent contraction in veins. In canine femoral arteries, the relaxation is prevented by inhibitors of cyclooxygenase. To determine the role of cyclooxygenase in the contraction evoked by arachidonic acid in the veins, rings of canine femoral and intrapulmonary veins, with and without endothelium, were suspended in organ chambers and set at their optimum length for isometric tension measurements. In rings of femoral and pulmonary vein contracted with norepinephrine, arachidonic acid produced a concentration-dependent increase in tension that was eliminated by removal of the endothelium or by treatment with the inhibitors of cyclooxygenase (indomethacin, meclofenamate, or acetylsalicyclic acid). The contractions were not prevented by inhibitors of thromboxane synthetase or prostacyclin synthetase or lipoxygenase. Pulmonary and femoral veins with or without endothelium relaxed to low, but contracted to high concentrations of prostacyclin and prostaglandin E2. Prostaglandin F2 alpha caused endothelium-independent contractions in both blood vessels. The present study suggests that the endothelium-dependent contractions to arachidonic acid observed in canine veins are mediated by prostanoids other than thromboxane and prostacyclin.

Interleukin-2 in human amniotic fluid during pregnancy and parturition: implications for prostaglandin E2 release by fetal membranes

1995 ◽  
Vol 29 (3) ◽  
pp. 197-208 ◽  
Author(s):  
Alessandra Zicari ◽  
Carlo Ticconi ◽  
Nino Pasetto ◽  
Anna Losardo ◽  
Annarita Salerno ◽  
...  
Keyword(s):  
Amniotic Fluid ◽  
Prostaglandin E2 ◽  
Interleukin 2 ◽  
Fetal Membranes ◽  
Human Amniotic Fluid

PGE2, PGF2 alpha, 6-keto-PGF1 alpha, and TxB2 synthesis along the rabbit nephron

1987 ◽  
Vol 252 (1) ◽  
pp. F53-F59 ◽  
Author(s):  
N. Farman ◽  
P. Pradelles ◽  
J. P. Bonvalet
Keyword(s):  
Arachidonic Acid ◽  
Prostaglandin E2 ◽  
Proximal Tubule ◽  
Enzyme Immunoassay ◽  
Thick Ascending Limb ◽  
Pge2 Synthesis ◽  
Nephron Segments ◽  
Prostaglandin F2 Alpha ◽  
Collecting Tubule ◽  
Cortical Collecting Tubule

The capacity of synthesis of prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha), 6-keto-PGF1 alpha, and thromboxane (TxB2) along the rabbit nephron was determined. A sensitive enzyme immunoassay was applied to isolated nephron segments, from the glomerulus to the terminal collecting tubule. The three prostaglandins and thromboxane (PG) were measured on the same samples after incubation in the presence of arachidonic acid. In the glomerulus, PGE2 synthesis (29.4 +/- 3.3 pg X glomerulus-1 X 30 min-1) represented 60% of the sum of the four PGs. PGF2 alpha and 6-keto-PGF1 alpha represented 22 and 17%, respectively, and TxB2 1.4%. The contribution of each PG to tubular synthesis was different, since at least 90% of PG synthesis consisted of PGE2. In the medullary collecting tubule (MCT), by far the major tubular site of PG synthesis, it was 809.6 +/- 140.8 pg X mm-1 X 30 min-1 for PGE2, 17.7 +/- 7.2 for PGF2 alpha, 8.3 +/- 1.9 for 6-keto-PGF1 alpha and 0.24 +/- 0.08 for TxB2. These relative proportions were roughly respected all along the tubule. Values were much lower in the convoluted and straight portions of the proximal tubule (proximal convoluted tubule: PGE2 8.2 +/- 2.0, PGF2 alpha 0.4 +/- 0.06, 6-keto-PGF1 alpha 0.26 +/- 0.04, TxB2 0.017) and the medullary and cortical thick ascending limb of the loop. They increased regularly along the distal structures of the tubule (light portion of the cortical collecting tubule (CCT1): PGE2 228.3 +/- 20.4, PGF2 alpha 4.34 +/- 0.6, 6-keto-PGF1 alpha 1.8 +/- 0.3, TxB2 0.22 +/- 0.07).(ABSTRACT TRUNCATED AT 250 WORDS)

Release of arachidonic acid metabolites by human fetal membranes: Interrelationship between leukotriene B4 and prostaglandin E2

1995 ◽  
Vol 49 (4) ◽  
pp. 197-204 ◽  
Author(s):  
Carlo Ticconi ◽  
Alessandra Zicari ◽  
Giuseppe Ponderi ◽  
Annarita Salerno ◽  
Alessandro Mauri ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Prostaglandin E2 ◽  
Leukotriene B4 ◽  
Fetal Membranes ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites

Testosterone Potentiation of Ionophore and ADP Induced Platelet Aggregation : Relationship to Arachidonic Acid Metabolism

1981 ◽  
Vol 46 (02) ◽  
pp. 538-542 ◽  
Author(s):  
R Pilo ◽  
D Aharony ◽  
A Raz
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Unsaturated Fatty Acids ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Arachidonic Acid Metabolism ◽  
Ionophore A23187 ◽  
Low Concentrations ◽  
Induced Aggregation

SummaryThe role of arachidonic acid oxygenated products in human platelet aggregation induced by the ionophore A23187 was investigated. The ionophore produced an increased release of both saturated and unsaturated fatty acids and a concomitant increased formation of TxA2 and other arachidonate products. TxA2 (and possibly other cyclo oxygenase products) appears to have a significant role in ionophore-induced aggregation only when low concentrations (<1 μM) of the ionophore are employed.Testosterone added to rat or human platelet-rich plasma (PRP) was shown previously to potentiate platelet aggregation induced by ADP, adrenaline, collagen and arachidonic acid (1, 2). We show that testosterone also potentiates ionophore induced aggregation in washed platelets and in PRP. This potentiation was dose and time dependent and resulted from increased lipolysis and concomitant generation of TxA2 and other prostaglandin products. The testosterone potentiating effect was abolished by preincubation of the platelets with indomethacin.

Pretreatment of Human Platelets with Plasmin Inhibits Responses toThrombin, but Potentiates Responses to Low Concentrations of Aggregating Agents, Including the Thrombin Receptor Activating Peptide, SFLLRN

1997 ◽  
Vol 77 (04) ◽  
pp. 741-747 ◽  
Author(s):  
R L Kinlough-Rathbone ◽  
D W Perry ◽  
M L Rand ◽  
M A Packham
Keyword(s):  
Arachidonic Acid ◽  
Platelet Activating Factor ◽  
Human Platelets ◽  
Thrombin Receptor ◽  
Fibrinolytic Agents ◽  
Albumin Solution ◽  
Fibrinogen Receptor ◽  
Low Concentrations ◽  
Induced Aggregation

SummaryEffects of plasmin on platelets, that influence subsequent responses to aggregating agents, are relevant to attempts to prevent rethrombosis following administration of fibrinolytic agents. We describe plasmin-induced inhibition of platelet responses to thrombin, but potentiation of responses to other aggregating agents. Washed human platelets were labeled with 14C-serotonin, treated for 30 min at 37° C with 0, 0.1 or 0.2 CU/ml of plasmin, followed by aprotinin, washed and resuspended in a Tyrode-albumin solution with apyrase. Incubation with 0.2 CU/ml of plasmin almost completely inhibited thrombin-induced (0.1 U/ml) aggregation, release of 14C-serotonin, and increase in cytosolic [Ca2+]. In contrast, with plasmin-pretreated platelets, aggregation and release of 14C-serotonin were strongly potentiated in response to low concentrations of the thrombin receptor-activating peptide SFLLRN, ADP, platelet-activating factor, collagen, arachidonic acid, the thromboxane mimetic U46619, and the calcium ionophores A23187 and ionomycin. Aspirin or RGDS partially inhibited potentiation. Plasmin-pretreated platelets resuspended in plasma anticoagulated with FPRCH2C1 (PPACK) also showed enhanced responses to aggregating agents other than thrombin. The contrasting effects on responses to thrombin and SFLLRN are noteworthy. Plasmin cleaves GPIIb/IIIa so that it becomes a competent fibrinogen receptor, and binding of 125I-fibrinogen during ADP-induced aggregation was greatly potentiated within 10 s. Potentiation of aggregation by other agonists may be due to increased binding of released fibrinogen. Thus, platelets freed from a thrombus may have increased responsiveness to low concentrations of aggregating agents other than thrombin. These results provide further support for the use of inhibitors of platelet reactions in conjunction with administration of fibrinolytic agents.

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