Renin release selectively stimulated by prostaglandin I2 in isolated rat glomeruli

1982 ◽  
Vol 243 (3) ◽  
pp. F276-F283 ◽  
Author(s):  
W. H. Beierwaltes ◽  
S. Schryver ◽  
E. Sanders ◽  
J. Strand ◽  
J. C. Romero
Keyword(s):  
Arachidonic Acid ◽  
Microsomal Fraction ◽  
Direct Interaction ◽  
Renin Release ◽  
Krebs Solution ◽  
Prostaglandin I2 ◽  
Pge2 Synthesis ◽  
Significant Release ◽  
Arachidonic Acid Concentration ◽  
Layer Chromatography

Renal glomeruli were isolated from rat kidneys using a passive mechanical sieving technique. Glomerular microsomal fraction, glomerular homogenate, or intact glomeruli were incubated with [1-14C]arachidonic acid, and the profile of prostaglandin (PG) synthesis was determined by thin-layer chromatography. The three incubation systems produced 15.3, 20.8, and 40.4% 6-keto-PGF1 alpha; 19.1, 23.5, and 15.3 PGF2 alpha; 5.7, 9.1, and 3.9% thromboxane (TX) B2; 36.0, 35.1, and 37.0% PGE2; and 23.9, 11.3, and 3.4% PGD2, respectively. Glomeruli were placed in suspension within glass chambers and superfused with Krebs solution. Superfusion with 1.6 x 10(-4) M arachidonic acid stimulated a significant release of renin from glomeruli, whereas 2.7 x 10(-6) M PGE1, PGE2, PGF2 alpha, TXB2, PGD2, or a stable analog of PGH2 had no effect on renin. When the rapid breakdown of PGI2 was counteracted by either increasing the concentration to 1.7 x 10(-4) M or stabilizing in Krebs at pH 9.4, it stimulated a significant increase in renin release. Reducing the arachidonic acid concentration to 1.6 x 10(-5) M eliminated both renin release and PGI2 synthesis, while increased PGE2 synthesis persisted. Finally, using an inhibitor of PGI2 synthesis, azo analog 1 (2.8 x 10(-6) M), 6-keto-PGF1 alpha produced in response to arachidonic acid was eliminated, as was the concurrent release of renin, but PGE2 synthesis was not affected. These results suggest that the mechanism of direct interaction between renal PG and renin in isolated glomeruli is selectively due to the action of PGI2.

Interaction of the prostaglandin and renin-angiotensin systems in isolated rat glomeruli

1980 ◽  
Vol 239 (6) ◽  
pp. F602-F608 ◽  
Author(s):  
W. H. Beierwaltes ◽  
S. Schryver ◽  
P. S. Olson ◽  
J. C. Romero
Keyword(s):  
Arachidonic Acid ◽  
Angiotensin Ii ◽  
Direct Evidence ◽  
Ringer Solution ◽  
Renin Release ◽  
Adrenergic Agonist ◽  
Beta Adrenergic ◽  
Significant Release ◽  
Pg E2 ◽  
Beta Adrenergic Agonist

Renal glomeruli were isolated from rat kidneys using a passive mechanical sieving technique. Suspensions of 40–50 mg glomeruli were placed in glass chambers and superfused by a modified Krebs-Ringer solution. Effluent collections of 10-min fractions were measured for renin or prostaglandin (PG) E2 concentration using radioimmunoassays. The perfusate was altered to contain either the beta-adrenergic agonist isoproterenol, angiotensin II, or arachidonic acid. Isoproterenol at 1.78 or 8.1 X 10(-4) M produced a significant release of renin, but the concentration of PGE2 was unaffected. Isoproterenol-stimulated renin release was blocked by 1.2 X 10(-4) M propranolol but was unaffected by 6.3 X 10(-6) M meclofenamate. Angiotensin II at 4 or 40 X 10(-9) M altered neither renin nor PGE2. Arachidonic acid administered at 1.6 or 16.0 X 10(-5) M produced a marked increase in PG synthesis and stimulated a significant release of renin. Treatment of glomeruli with 6.3 X 10(-6) M meclofenamate attenuated PGE2 synthesis and abolished renin release, but 1.2 X 10(-4) M propranolol had no effect on PG synthesis or the coincident release of renin. These results give direct evidence of an interrelating mechanism between renal prostaglandins and renin release that is independent of external tubular or hemodynamic stimuli and show that the beta-adrenergic pathway of renin stimulation is independent of any modifying influence exerted by prostaglandins.

scholarly journals Subcellular localization of the PGE2 synthesis activity in mouse resident peritoneal macrophages.

1984 ◽  
Vol 159 (1) ◽  
pp. 89-102 ◽  
Author(s):  
C Darte ◽  
H Beaufay
Keyword(s):  
Arachidonic Acid ◽  
Half Life ◽  
Kinetic Studies ◽  
Peritoneal Macrophages ◽  
Pge2 Synthesis ◽  
Quantitative Basis ◽  
Synthesis Activity ◽  
Pg E2 ◽  
The Stability ◽  
Layer Chromatography

The aim of this work was to establish, on a quantitative basis, the subcellular distribution of the enzyme system that converts arachidonic acid into prostaglandin (PG) E2 in mouse resident peritoneal (MRP) macrophages. Kinetic studies were conducted on cell-free extracts derived from cells cultivated for 1 d, using [1-14C]arachidonic acid as substrate and measuring the label in PGE2 after extraction and thin layer chromatography. The activity was synergistically enhanced by L-adrenaline and reduced glutathione, inhibited by indomethacin, and linearly related to the concentration of the cell-free extract. It was labile at 0 degrees C in the medium used for homogenization and fractionation of the cells (half-life less than 2 h). Addition of catalase (0.15 mg/ml) to the suspension medium increased the initial activity (by congruent to 70%) and the stability (half-life congruent to 6 h) of the enzyme in cytoplasmic extracts. It enabled us to establish the density distribution after isopycnic centrifugation in a linear gradient of sucrose. The sample centrifuged consisted of untreated cytoplasmic extracts, or cytoplasmic extracts treated with digitonin and Na pyrophosphate. Comparison of the centrifugation behavior of PGE2 synthesis activity with that of various enzymes used as reference for the major subcellular entities has revealed that PGE2 synthesis fairly fits the density profile of sulfatase C in each case. The conclusion is that at least the rate-limiting reaction in the conversion of arachidonic acid into PGE2 is catalyzed by an enzyme associated with the endoplasmic reticulum.

scholarly journals Berberine, A Phytoalkaloid, Inhibits Inflammatory Response Induced by LPS through NF-Kappaβ Pathway: Possible Involvement of the IKKα

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4733
Author(s):  
Kiran Reddi ◽  
Hanxuan Li ◽  
Wei Li ◽  
Sarada Tetali
Keyword(s):  
Arachidonic Acid ◽  
Molecular Modeling ◽  
Direct Interaction ◽  
Ligand Binding Site ◽  
Quantitative Real Time Pcr ◽  
Tnf Α ◽  
Molecular Modeling Studies ◽  
Therapeutic Properties ◽  
Cox 2 ◽  
Activated Monocytes

Berberine (BBR), a plant alkaloid, is known for its therapeutic properties of anticancer, cardioprotective, antidiabetic, hypolipidemic, neuroprotective, and hepatoprotective activities. The present study was to determine the molecular mechanism of BBR’s pharmacological activity in human monocytic (THP-1) cells induced by arachidonic acid (AA) or lipopolysaccharide (LPS). The effect of BBR on AA/LPS activated proinflammatory markers including TNF-α, MCP-1, IL-8 and COX-2 was measured by ELISA or quantitative real-time PCR. Furthermore, the effect of BBR on LPS-induced NF-κB translocation was determined by immunoblotting and confocal microscopy. AA/ LPS-induced TNF-α, MCP-1, IL-6, IL-8, and COX-2 markers were markedly attenuated by BBR treatment in THP-1 cells by inhibiting NF-κB translocation into the nucleus. Molecular modeling studies suggested the direct interaction of BBR to IKKα at its ligand binding site, which led to the inhibition of the LPS-induced NF-κB translocation to the nucleus. Thus, the present study demonstrated the anti-inflammatory potential of BBR via NF-κB in activated monocytes, whose interplay is key in health and in the pathophysiology of atherosclerotic development in blood vessel walls. The present study findings suggest that BBR has the potential for treating various chronic inflammatory disorders.

scholarly journals A pertussis-toxin-sensitive protein controls exocytosis in chromaffin cells at a step distal to the generation of second messengers

1991 ◽  
Vol 274 (2) ◽  
pp. 339-347 ◽  
Author(s):  
J M Sontag ◽  
D Thierse ◽  
B Rouot ◽  
D Aunis ◽  
M F Bader
Keyword(s):  
Arachidonic Acid ◽  
Cyclic Amp ◽  
G Protein ◽  
Pertussis Toxin ◽  
Chromaffin Cells ◽  
Second Messengers ◽  
Catecholamine Release ◽  
Secretory Process ◽  
Permeabilized Cells ◽  
Arachidonic Acid Concentration

The role of GTP-binding proteins (G-proteins) in the secretory process in chromaffin cells was investigated by studying the effects of pertussis toxin (PTX) on catecholamine release and generation of various second messengers. PTX was found to stimulate the catecholamine secretion induced by nicotine, 59 mM-K+ or veratridine. PTX also potentiated Ca2(+)-evoked catecholamine release from permeabilized chromaffin cells, suggesting that PTX substrate(s) regulate the exocytotic machinery at a step distal to the rise in intracellular Ca2+. We have investigated the possible intracellular pathways involved in the stimulation of secretion by PTX. PTX did not modify the translocation of protein kinase C (PKC) to membranes in intact or permeabilized cells; in addition, neither inhibitors nor activators of PKC had any effect on catecholamine release induced by PTX. Thus it seems unlikely that the effect of PTX on secretion is mediated by activation of PKC. The effect of PTX is also cyclic AMP-independent, as PTX did not change cytoplasmic cyclic AMP levels. The relationship between PTX treatment and arachidonic acid release was also examined. We found that an increase in cytoplasmic arachidonic acid concentration enhanced Ca2(+)-evoked catecholamine release in permeabilized cells, but arachidonic acid did not mimic the effect of PTX on the Ca2(+)-dose-response curve for secretion. Furthermore, PTX did not significantly modify the release of arachidonic acid measured in resting or stimulated chromaffin cells, suggesting that the stimulatory effect of PTX on secretion is not mediated by an activation of phospholipase A2. Taken together, these results suggest that PTX may modulate the intracellular machinery of secretion at a step distal to the generation of second messengers. In alpha-toxin-permeabilized cells, full retention of the PTX-induced activation of secretion was observed even 30 min after permeabilization. In contrast, when chromaffin cells were permeabilized with streptolysin-O (SLO), there was a marked progressive loss of the PTX effect. We found that SLO caused the rapid leakage of three G-protein alpha-subunits which are specifically ADP-ribosylated by PTX. We propose that a PTX-sensitive G-protein may play an inhibitory role in the final stages of the Ca2(+)-evoked secretory process in chromaffin cells.

Cytochrome P-450 mediated biotransformation of organic nitrates

1990 ◽  
Vol 68 (12) ◽  
pp. 1552-1557 ◽  
Author(s):  
Bernard J. McDonald ◽  
Brian M. Bennett
Keyword(s):  
Glyceryl Trinitrate ◽  
Microsomal Fraction ◽  
Direct Interaction ◽  
Organic Nitrate ◽  
Organic Nitrates ◽  
Aerobic Conditions ◽  
First Order ◽  
Preferential Formation ◽  
First Order Kinetics ◽  
Cytochrome P 450

The vascular biotransformation of organic nitrates appears to be a prerequisite for their action as vasodilators. In the current study, we assessed the involvement of cytochrome P-450 in the denitration of glyceryl trinitrate and the enantiomers of isoidide dinitrate. Denitration of organic nitrates by the microsomal fraction of rat liver was NADPH dependent and followed apparent first-order kinetics. Under aerobic conditions, the t1/2 of D-isoidide dinitrate was significantly shorter than that of L-isoidide dinitrate (11.9 vs. 14.1 min, p ≤ 0.05), which is consistent with the greater potency of the D-enantiomer for vasodilation. Under anaerobic conditions, the denitration of glyceryl trinitrate was very rapid (t1/2 approximately 30 s). Organic nitrate biotransformation was inhibited by carbon monoxide, SKF 525A, and dioxygen. This suggests that the biotransformation of organic nitrates can occur through the direct interaction with the heme moiety of cytochrome P-450. The biotransformation of glyceryl trinitrate was catalyzed preferentially by those isoenzymes induced by phenobarbital. The biotransformation of glyceryl trinitrate was regioselective for 1,3-glyceryl dinitrate formation except in phenobarbital-induced microsomes under aerobic conditions, in which preferential formation of 1,2-glyceryl dinitrate occurred. These data suggest that cytochrome P-450 is involved in the biotransformation of organic nitrates and raises the possibility that vascular cytochrome P-450 may play a role in the mechanism-based biotransformation of organic nitrates, the result of which is vascular smooth muscle relaxation.Key words: cytochrome P-450, glyceryl trinitrate, isoidide dinitrate, biotransformation, liver.

Inhibition Of Platelet Aggregation, Malonyldialdehyde And Thromboxane Formation By Hydroperoxides Of Arachidonic Acid

1981 ◽  
Author(s):  
D Aharonv ◽  
J B Smith ◽  
M J Silver
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Lipoxygenase Pathway ◽  
Dose Dependent Fashion ◽  
Induced Aggregation ◽  
Layer Chromatography ◽  
Dose Dependent ◽  
Thromboxane Formation

The arachidonate hydroperoxides 12-HPETE and 15-HPETE were biosynthesized from arachidonic acid using partially purified human platelet lipoxygenase or soybean lipoxidase respectively, and isolated by thin layer chromatography. Both compounds inhibited the arachidonic acid- induced aggregation of washed human platelets, suspended in calcium-free Krebs Henseleit solution, in a dose dependent fashion at concentrations between 1 and 50 uM. No inhibition was seen with up to 100 uM of these hydroperoxides when platelet -rich plasma was used. 12-HPETE (in micromolar concentrations) inhibited the formation of both thromboxane B2 (radioimmunoassay) and malonyldialdehyde (spectrophotometrie assay) when washed platelets were incubated with arachidonic acid. The 12-hydroxide, 12-HETE also inhibited platelet aggregation and thromboxane formation, but was less potent than 12-HPETE. We suggest that arachidonate hydroperoxide generated in platelets via the lipoxygenase pathway modulates platelet aggregation induced by arachidonic acid by inhibiting thromboxane formation.

Prostaglandins and renin release in vitro

1981 ◽  
Vol 240 (6) ◽  
pp. E609-E614
Author(s):  
C. S. Lin ◽  
H. Iwao ◽  
S. Puttkammer ◽  
A. M. Michelakis
Keyword(s):  
Arachidonic Acid ◽  
Renal Cortex ◽  
The Other ◽  
Renin Release ◽  
Eicosatetraenoic Acid ◽  
Juxtaglomerular Cells ◽  
Prostaglandin F2 Alpha ◽  
Prostaglandin System

The present studies were undertaken to explore further the role of prostaglandins in the release of renin from the renal cortex. To provide the best assessment of renin release, renin was determined by a radioimmunoassay for the direct measurement of renin. Slices of mouse renal cortex were incubated at 37 degrees C with arachidonic acid (AA), 5,8,11,14-eicosatetraenoic acid (ETA), indomethacin, prostaglandins, and synthetic prostaglandin endoperoxide analogue (EPA). Our results showed that AA at 1.5 X 10(-8) M significantly increased renin release at 10 and 30 min of incubation. This renin increase ws abolished by either ETA or indomethacin. Prostaglandin F2 alpha (PGF2 alpha) also significantly stimulated renin release at 10 and 60 min. PGE2 and 16,16-dimethyl PGE2 (DMPGE2) showed much less renin release-stimulating activity. EPA and PGI2 on the other hand very strongly stimulated renin release. However, at higher concentrations the stimulating effect of PGI2 and EPA disappeared and even became inhibitory in the case of EPA. Other prostaglandins were found to have no effect on renin release. The results suggest that the prostaglandin system directly affects renin release from the juxtaglomerular cells independent of systemic neurogenic and hemodynamic influences.

scholarly journals Fatty acid stimulation of membrane phosphatidylinositol hydrolysis by brain phosphatidylinositol phosphodiesterase

1979 ◽  
Vol 178 (2) ◽  
pp. 497-500 ◽  
Author(s):  
R F Irvine ◽  
A J Letcher ◽  
R M Dawson
Keyword(s):  
Arachidonic Acid ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Acid Content ◽  
Microsomal Fraction ◽  
Fatty Acid Content ◽  
Membrane Bound ◽  
Liver Microsomal Fraction ◽  
Hydrolysis Of ◽  
Stimulation Of

The hydrolysis of membrane-bound phosphatidylinositol in rat liver microsomal fraction by the soluble phosphatidylinositol phosphodiesterase from rat brain was markedly stimulated by oleic acid or arachidonic acid. The stimulation did not require added calcium, although it was abolished by EDTA. Lysophosphatidylcholine also totally suppressed the stimulation. A possible role for the fatty acid content of a membrane in controlling phosphatidylinositol turnover is suggested.

The thrombin-dependent enrichment of alkenylacyl ethanolamine phosphoglyceride with [14C]eicosapentaenoic and [3H]arachidonic acids in prelabelled human platelets

1987 ◽  
Vol 65 (4) ◽  
pp. 405-408 ◽  
Author(s):  
B. J. Weaver ◽  
B.J. Holub
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Human Platelet ◽  
Platelet Reactivity ◽  
Human Subjects ◽  
Human Platelets ◽  
Arachidonic Acids ◽  
Layer Chromatography ◽  
Hydrolysis Of ◽  
Individual Human

The thrombin-dependent enrichment of alkenylacyl ethanolamine phosphoglyceride in [14C]eicosapentaenoic acid ([14C]EPA) was demonstrated and compared with [3H]arachidonic acid ([3H]AA) following the simultaneous prelabelling of individual human platelet phospholipids with these two fatty acids. The alkenylacyl, diacyl, and alkylacyl classes of ethanolamine phosphoglycerides (PE) were separated by thin-layer chromatography as their acetylated derivatives after hydrolysis of the parent phospholipid with phospholipase C. The ratios of [3H]/[14C] for the increased radioactivity appearing in alkenylacyl PE following 60 and 120 s of thrombin stimulation were the same as the corresponding ratio (2.0) found in the choline phosphoglycerides (PC) from control (unstimulated) platelets. These results suggest no significant selectivity between EPA and AA in the thrombin-stimulated transfer of these fatty acids from diacyl PC to alkenylacyl PE. The present findings may possibly bear some relevance to the altered platelet reactivity and (or) decreased thromboxane A2 formation observed in human subjects following the ingestion of marine lipid containing EPA.

Sign in / Sign up

Export Citation Format

Share Document