scholarly journals Factors regulating the production of prostaglandin E2 and prostacyclin (prostaglandin I2) in rat and human adipocytes

1987 ◽  
Vol 247 (2) ◽  
pp. 389-394 ◽  
Author(s):  
B Richelsen
Keyword(s):  
Angiotensin Ii ◽  
Cyclic Amp ◽  
Prostaglandin E2 ◽  
Acetylsalicylic Acid ◽  
Dependent Manner ◽  
Human Adipocytes ◽  
Prostaglandin I2 ◽  
Concentration Dependent Manner ◽  
Rat Adipocytes ◽  
Isolated Adipocytes

The regulation of PGE2 (prostaglandin E2) and PGI2 (prostaglandin I2; prostacyclin) formation was investigated in isolated adipocytes. The formation of both PGs was stimulated by various lipolytic agents such as isoproterenol, adrenaline and dibutyryl cyclic AMP. During maximal stimulation the production of PGE2 and PGI2 (measured as 6-oxo-PGF1 alpha) was 0.51 +/- 0.04 and 1.21 +/- 0.09 ng/2 h per 10(6) cells respectively. Thus PGI2 was produced in excess of PGE2 in rat adipocytes. The production of the PGs was inhibited by indomethacin and acetylsalicylic acid in a concentration-dependent manner. The half-maximal effective concentration of indomethacin was 328 +/- 38 nM and that of acetylsalicylic acid was 38.5 +/- 5.3 microM. The PGs were maximally inhibited by 70-75% after incubation for 2 h. In contrast with their effect on PG production, the two agents had a small potentiating effect on the stimulated lipolysis (P less than 0.05). The phospholipase inhibitors mepacrine and chloroquine inhibited both PG production and triacylglycerol lipolysis and were therefore unable to indicate whether the PG precursor, arachidonic acid, originates from phospholipids or triacylglycerols in adipocytes. Angiotensin II significantly (P less than 0.05) stimulated both PGE2 and PGI2 production in rat adipocytes without affecting triacylglycerol lipolysis. Finally, it was shown that PGE2 and PGI2 were also produced in human adipocytes, although in smaller quantities than in rat adipocytes. It is concluded that the production of PGs in isolated adipocytes is regulated by various hormones. Moreover, at least two separate mechanisms for PG production may exist in adipocytes: (1) a mechanism that is activated concomitantly with triacylglycerol lipolysis (and cyclic AMP) and (2) an angiotensin II-sensitive, but lipolysis (and cyclic AMP)-independent mechanism.

scholarly journals Renal microvascular actions of calcitonin gene-related peptide

1998 ◽  
Vol 274 (6) ◽  
pp. F1078-F1085 ◽  
Author(s):  
Martina Reslerova ◽  
Rodger Loutzenhiser
Keyword(s):  
Angiotensin Ii ◽  
Rat Kidney ◽  
Elevated Pressure ◽  
Calcitonin Gene Related Peptide ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Renal Vasoconstriction ◽  
Related Peptide ◽  
Calcitonin Gene

Calcitonin gene-related peptide (CGRP) is a potent vasodilator that is suggested to act via ATP-sensitive K channels (KATP). In the present study, we examined the actions of CGRP on pressure- and angiotensin II-induced vasoconstriction, using the in vitro perfused hydronephrotic rat kidney. Elevated pressure (from 80 to 180 mmHg) and 0.1 nM angiotensin II elicited similar decreases in afferent diameter in this model. CGRP inhibited myogenic reactivity in a concentration-dependent manner, completely preventing pressure-induced constriction at 10 nM (95 ± 10% inhibition). These effects were partially attenuated by 10 μM glibenclamide (62 ± 16% inhibition, P = 0.025), indicating both KATP-dependent and -independent actions of CGRP. In contrast, 10 nM CGRP inhibited angiotensin II-induced vasoconstriction by only 54 ± 11%, and this action was not affected by glibenclamide (41 ± 11%, P = 0.31). CGRP also inhibited the efferent arteriolar response to angiotensin II in the absence and presence of glibenclamide. Pinacidil (1.0 μM), a KATP opener also preferentially inhibited pressure- vs. angiotensin II-induced vasoconstriction (97 ± 5 and 59 ± 13% inhibition, respectively; P = 0.034). We conclude that the renal vasodilatory mechanisms of CGRP are pleiotropic and involve both KATP-dependent and -independent pathways. The effectiveness of CGRP in opposing renal vasoconstriction and the role of KATP in this action appear to depend on the nature the underlying vasoconstriction. We suggest that this phenomenon reflects an inhibition of KATP activation by angiotensin II.

Control of neurotransmission by prostaglandins in canine trachealis smooth muscle

1984 ◽  
Vol 57 (1) ◽  
pp. 129-134 ◽  
Author(s):  
E. H. Walters ◽  
P. M. O'Byrne ◽  
L. M. Fabbri ◽  
P. D. Graf ◽  
M. J. Holtzman ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Prostaglandin E2 ◽  
Electrical Field Stimulation ◽  
Tracheal Smooth Muscle ◽  
Dependent Manner ◽  
Field Stimulation ◽  
Electrical Field ◽  
Similar Time ◽  
Concentration Dependent Manner ◽  
Contractile Responses

Contractile responses of canine tracheal smooth muscle to electrical field stimulation diminished over a 2-h period of incubation. However, addition of indomethacin (10(-5) M) for a similar time not only prevented this inhibition of contractile response, but actually markedly increased the response to electrical field stimulation, suggesting that prostaglandins were responsible for the time-dependent inhibition. Measured prostaglandin E2 increased in the tissue bath over 2 h in control tissues. Addition of prostaglandin E2 to the tissue produced similar inhibition of contractile responses to electrical field stimulation in a concentration-dependent manner. In contrast, incubation alone, treatment with indomethacin, or addition of prostaglandin E2 had little, if any, effect on contractions induced by acetylcholine. We conclude that the release of prostaglandins from canine tracheal smooth muscle that occurs with time has a predominantly inhibitory effect on cholinergic neurotransmission at a prejunctional site.

Potentiation of angiotensin II-stimulated vascular contraction by lithium

1995 ◽  
Vol 268 (5) ◽  
pp. H2009-H2016
Author(s):  
M. E. Ullian ◽  
L. G. Walsh ◽  
K. C. Wong ◽  
C. J. Allan
Keyword(s):  
Angiotensin Ii ◽  
Inositol Phosphate ◽  
Cytosolic Calcium ◽  
Rat Aorta ◽  
Dependent Manner ◽  
Ang Ii ◽  
Concentration Dependent Manner ◽  
Adrenergic Agents ◽  
Phosphoinositide Signaling ◽  
Protein Kinase C Inhibitor

Previous studies have suggested that lithium prolongs or enhances vascular contractions stimulated by alpha-adrenergic agents. The present study was performed to determine whether a similar phenomenon occurs with angiotensin II (ANG II)-stimulated contractions and whether this phenomenon results from interactions with the phosphoinositide signaling system. Contractions of rat aortic rings with 100 nM ANG II were 38% greater in the presence of 20 mM LiCl than in its absence (0.47 +/- 0.07 vs. 0.34 +/- 0.05 g tension/mg dry tissue wt, P < 0.01). The effects of lithium on inositol phosphate responses, diacylglycerol responses, and intracellular calcium concentration on single or repeated stimulations with ANG II were then examined in vascular smooth muscle cells cultured from rat aorta. Cells exposed twice to 100 nM ANG II contained 50% lower inositol trisphosphate levels (InsP3) and 10% lower diacylglycerol levels than cells exposed to ANG II only once. LiCl or lithium acetate abolished these desensitizations in a concentration-dependent manner. Similarly, InsP3 and diacylglycerol responses to a single exposure of ANG II were heightened by lithium (by 75 and 25%, respectively), and the duration of the responses was prolonged by lithium (5- and 2-fold, respectively). In contrast, ANG II-stimulated calcium transients were not enhanced or prolonged by lithium, nor was desensitization of ANG II-stimulated cytosolic calcium mobilization upon serial exposures abolished by lithium. When ring contraction studies were repeated in the presence of the protein kinase C inhibitor staurosporine (150 nM), lithium no longer potentiated ANG II contractions [0.38 +/- 0.03 (control) vs. 0.35 +/- 0.06 g tension/mg dry tissue wt (lithium)].(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II activates two distinct cation conductances in a concentration dependent manner which display TRPC like properties

2007 ◽  
Vol 21 (5) ◽  
Author(s):  
Sohag Nafis Saleh ◽  
Anthony P Albert ◽  
Claire M Peppiatt‐ Wildman ◽  
William A Large
Keyword(s):  
Angiotensin Ii ◽  
Dependent Manner ◽  
Concentration Dependent Manner

scholarly journals Angiotensin II-Induced Mitogen-Activated Protein Kinase Phosphatase-1 Expression in Bovine Adrenal Glomerulosa Cells: Implications in Mineralocorticoid Biosynthesis

Endocrinology ◽  
2007 ◽  
Vol 148 (11) ◽  
pp. 5573-5581 ◽  
Author(s):  
Andrés J. Casal ◽  
Stéphane Ryser ◽  
Alessandro M. Capponi ◽  
Carine F. Wang-Buholzer
Keyword(s):  
Angiotensin Ii ◽  
Mapk Pathway ◽  
Fold Increase ◽  
Zona Glomerulosa ◽  
Mitogen Activated Protein Kinase ◽  
Receptor Subtype ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Aldosterone Production ◽  
Glomerulosa Cells

Angiotensin II (AngII) stimulates aldosterone biosynthesis in the zona glomerulosa of the adrenal cortex. AngII also triggers the MAPK pathways (ERK1/2 and p38). Because ERK1/2 phosphorylation is a transient process, phosphatases could play a crucial role in the acute steroidogenic response. Here we show that the dual specificity (threonine/tyrosine) MAPK phosphatase-1 (MKP-1) is present in bovine adrenal glomerulosa cells in primary culture and that AngII markedly increases its expression in a time- and concentration-dependent manner (IC50 = 1 nm), a maximum of 548 ± 10% of controls being reached with 10 nm AngII after 3 h (n = 3, P &lt; 0.01). This effect is completely abolished by losartan, a blocker of the AT1 receptor subtype. Moreover, this AngII-induced MKP-1 expression is reduced to 250 ± 35% of controls (n = 3, P &lt; 0.01) in the presence of U0126, an inhibitor of ERK1/2 phosphorylation, suggesting an involvement of the ERK1/2 MAPK pathway in MKP-1 induction. Indeed, shortly after AngII-induced phosphorylation of ERK1/2 (220% of controls at 30 min), MKP-1 protein expression starts to increase. This increase is associated with a reduction in ERK1/2 phosphorylation, which returns to control values after 3 h of AngII challenge. Enhanced MKP-1 expression is essentially due to a stabilization of MKP-1 mRNA. AngII treatment leads to a 53-fold increase in phosphorylated MKP-1 levels and a doubling of MKP-1 phosphatase activity. Overexpression of MKP-1 results in decreased phosphorylation of ERK1/2 and aldosterone production in response to AngII stimulation. These results strongly suggest that MKP-1 is the specific phosphatase induced by AngII and involved in the negative feedback mechanism ensuring adequate ERK1/2-mediated aldosterone production in response to the hormone.

scholarly journals Regulation of Rat Mesangial Cell Migration by Platelet-Derived Growth Factor, Angiotensin II, and Adrenomedullin

1999 ◽  
Vol 10 (12) ◽  
pp. 2495-2502 ◽  
Author(s):  
MASAKAZU KOHNO ◽  
KENICHI YASUNARI ◽  
MIEKO MINAMI ◽  
HIROAKI KANO ◽  
KENSAKU MAEDA ◽  
...  
Keyword(s):  
Cell Migration ◽  
Angiotensin Ii ◽  
Growth Factor ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Inhibitory Effect ◽  
Platelet Derived Growth Factor ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Concentration Dependent Manner

Abstract. This study sought to determine whether platelet-derived growth factor (PDGF) and angiotensin II (AngII) stimulate migration of cultured rat glomerular mesangial cells. After finding that this was so, the effects of adrenomedullin (ADM) and cAMP-elevating agents on basal and stimulated mesangial cell migration were examined. Two isoforms of PDGF, AB and BB, stimulated migration in a concentration-dependent manner between 1 and 50 ng/ml, while the AA isoform lacked significant effect. AngII modestly but significantly stimulated migration in a concentration-dependent manner between 10-7 and 10-6 mol/L. Rat ADM significantly inhibited the PDGF BB- and AngII-stimulated migration in a concentration-dependent manner between 10-8 and 10-7 mol/L. Inhibition by rat ADM was accompanied by an increase in cellular cAMP. cAMP agonists or inducers such as 8-bromo cAMP, forskolin, and prostaglandin I2 also significantly reduced the stimulated migration. H 89, a protein kinase A (PKA) inhibitor, attenuated the inhibitory effect of ADM, and a calcitonin gene-related peptide (CGRP) receptor antagonist, human CGRP (8-37), abolished the inhibitory effects of rat ADM. These results suggest that PDGF AB and BB as well as AngII stimulate rat mesangial cell migration and that ADM can inhibit PDGF BB- and AngII-stimulated migration, at least in part through cAMP-dependent mechanisms likely to involve specific ADM receptors with which CGRP interacts. The adenylate cyclase/cAMP/PKA system may be involved in the migration-inhibitory effect of ADM in these cells.

Stimulatory effect of lithium on glucose transport in rat adipocytes is not mediated by elevation of IP1

1998 ◽  
Vol 275 (2) ◽  
pp. E272-E277 ◽  
Author(s):  
Xiaoli Chen ◽  
Ellen G. McMahon ◽  
Eric A. Gulve
Keyword(s):  
Glucose Uptake ◽  
Glucose Transport ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Transport Activity ◽  
Concentration Dependent Manner ◽  
Inositol 1 ◽  
Rat Adipocytes ◽  
Increase Glucose Uptake ◽  
Stimulation Of

Lithium has been shown to increase glucose uptake in skeletal muscle and adipose tissues. The therapeutic effect of lithium on bipolar disease is thought to be mediated by its inhibitory effect on myo-inositol-1-monophosphatase (IMPase). We tested the hypothesis that the stimulatory effect of lithium on glucose uptake results from inhibition of IMPase and the resultant accumulation of inositol monophosphates (IP1) by comparing the effects of lithium and a selective IMPase inhibitor, L-690,488, on isolated rat adipocytes. Insulin produced a concentration-dependent stimulation of 2-deoxy-d-[14C]glucose (2-DG) transport (10 μU/ml caused half-maximal activation). Acute exposure to lithium stimulated basal glucose transport activity in a concentration-dependent manner, with a threefold stimulation at 30 mM lithium. Lithium also potentiated insulin-stimulated 2-DG transport. Lithium produced a concomitant increase in IP1 accumulation. In contrast, L-690,488 increased IP1 to levels comparable to those of lithium without stimulatory effects on 2-DG transport. These results demonstrate that stimulatory effects of lithium on glucose transport are not mediated by the inhibition of IMPase and subsequent accumulation of IP1 in rat adipocytes.

The Relation of Blood Adenosine Triphosphate to Changes of Mood in Affective Disorders

1974 ◽  
Vol 125 (586) ◽  
pp. 268-274 ◽  
Author(s):  
Otto Hansen ◽  
Maria Dimitrakoudi
Keyword(s):  
Cyclic Amp ◽  
Adenosine Triphosphate ◽  
Whole Blood ◽  
Dependent Manner ◽  
Uridine Diphosphate ◽  
Healthy Human ◽  
Electroconvulsive Treatment ◽  
Concentration Dependent Manner ◽  
Depressive Patients

Peripheral whole blood uridine diphosphate glucose (UDPG) has been found to be significantly elevated in psychotic depression (Hansen, 1969; 1972a, b), and this was related to an equally significant lowering of whole blood adenosine triphosphate (ATP). Addition to healthy human blood of UDPG accelerated the hydrolysis of ATP in vitro (Hansen, 1972a), and UDPG concentration dependently enhanced the activity of a vegetable ATP di-phosphohydrolase (EC 3.6.1.5), which was also inhibited by adenosine 3’, 5′-cyclic monophosphate (cyclic AMP) in a concentration-dependent manner (Hansen, 1972b). Other workers have recently published a similar inhibition of a rat heart ATPase by cyclic AMP (Dietze and Hepp, 1972), and another research group have found that sodium-potassium exchange pump changes and changes in erythrocyte membrane ATPase activity correlate significantly with mood alterations in psychotic depressive patients (Dick, Dick, Le Poidevin and Naylor, 1972; Naylor, Dick, Dick, Le Poidevin and Whyte, 1973). This paper reports a study of the relationship between blood ATP levels and mood in patients suffering from manic-depressive predictable (Jenner, 1971) short term cycle psychotic states, and in depressive patients receiving electroconvulsive treatment.

Abstract P127: Angiotensin II Priming Enhances Prostaglandin E2 Vasoconstrictor Effects

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Maria P Kraemer ◽  
Fred Lamb ◽  
Richard M Breyer
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Kinase Inhibitor ◽  
Rho Kinase ◽  
Area Under The Curve ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Ang Ii ◽  
Concentration Dependent Manner ◽  
Femoral Arteries

Prostaglandins are key modulators of blood pressure and arterial tone. Prostaglandin E 2 (PGE 2 ), is a prostanoid that has vasodepressor effects; however, under certain circumstances PGE 2 can induce vasopressor responses. Recent reports demonstrated that sub-threshold concentrations of vasoconstrictors augment PGE 2 -mediated constriction in rat femoral arteries. However, whether angiotensin II (Ang II) could affect PGE 2 -mediated contraction is not known. Using a wire myograph, we demonstrated that PGE 2 had no significant effect on mouse femoral arterial rings at doses up to 1 μM. However, priming of arterial rings with 1 nM Ang II potentiated PGE 2 -evoked constriction in a concentration dependent manner (Area Under the Curve, AUC untreated 1.784 ± 0.353, AUC Ang II 23.27± 9.820, P<0.05). We tested femoral arteries from EP1, EP2, and EP3 receptor knockout mice. Only the EP3-/- arteries were unable to respond to PGE 2 after Ang II priming (figure below). Pretreatment of arterial rings with 1 μM losartan, an angiotensin receptor antagonist, blocked PGE 2 -induced constrictor effects primed with Ang II (% of KCl, Ang II 21.72 ± 5.296, Ang II + losartan 3.025 ± 1.046, n=3). We have determined that re-addition of extracellular Ca 2+ to a Ca 2+ -free artery restores PGE 2 -induced contractions (n=5) and that the Rho-kinase inhibitor Y-27632 blocks contraction (n=3). Taken together these data are consistent with angiotensin AT1 and prostaglandin EP3 receptors mediating a synergistic Rho-kinase-dependent contractile response. We are continuing to investigate the relationship between Ang II and PGE 2 to determine the physiological relevance this may have in modulating blood pressure.

EDRF-angiotensin II interactions in rat juxtamedullary afferent and efferent arterioles

1992 ◽  
Vol 263 (5) ◽  
pp. F900-F906 ◽  
Author(s):  
K. Ohishi ◽  
P. K. Carmines ◽  
E. W. Inscho ◽  
L. G. Navar
Keyword(s):  
Angiotensin Ii ◽  
Renin Angiotensin System ◽  
Biological Action ◽  
Dependent Manner ◽  
Ang Ii ◽  
Synthesis Inhibitor ◽  
Concentration Dependent Manner ◽  
Arteriolar Resistance ◽  
Constrictor Response

The in vitro blood-perfused juxtamedullary nephron technique was utilized to determine the contribution of endothelium-derived relaxing factor (EDRF) to resting renal arteriolar caliber and to evaluate the interaction between EDRF and angiotensin II (ANG II) in renal microvascular control. Video microscopy was employed to visualize rat afferent and efferent arterioles and to measure their responses to blockade of nitric oxide (NO), which has been shown to account for much of the biological action of EDRF. The NO synthesis inhibitor, N omega-nitro-L-arginine (L-NNA), elicited vasoconstriction in a concentration-dependent manner, with 1,000 microM L-NNA significantly reducing both afferent (16 +/- 3%) and efferent (13 +/- 1%) diameters. This concentration of L-NNA also blocked the vasodilator response to 10 microM acetylcholine, while responsiveness to sodium nitroprusside was maintained. Vasoconstrictor responses to 1,000 microM L-NNA were attenuated in kidneys from rats pretreated with enalaprilat or losartan, reducing afferent diameter by 7 +/- 1 (n = 8) and 3 +/- 1% (n = 10) of control, respectively. Efferent arteriolar responses to L-NNA were similarly attenuated by losartan. The constrictor response to 10 nM ANG II was not exaggerated by L-NNA, suggesting that ANG II does not stimulate EDRF synthesis. These observations indicate that EDRF is continuously released in a quantity sufficient to affect both afferent and efferent arterioles of juxtamedullary nephrons in vitro. Furthermore, ANG II blockade attenuates the vasoconstriction elicited by L-NNA, suggesting that EDRF interacts with the renin-angiotensin system to control juxtamedullary afferent and efferent arteriolar resistance.

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