prostaglandin-f1 and Hypertension

To evaluate the role of the vasoactive prostaglandins prostacyclin and thromboxane A2 in essential hypertension, the stable metabolites 6-keto-PGF1 alpha and thromboxane B2, respectively, were measured in plasma before and after therapy in 7 patients. During the placebo phase, plasma 6-keto-PGF1 alpha levels were significantly greater than normal. Plasma thromboxane B2 levels were not statistically different from those in normal subjects. After intravenous administration of labetalol to the point of blood pressure reduction, neither plasma 6-keto-PGF1 alpha nor thromboxane B2 values changed. With prolonged oral labetalol therapy and concurrent regulation of blood pressure, a significant decrease in plasma 6-keto-PGF1 alpha levels occurred while thromboxane B2 values remained unaltered. Elevation of plasma 6-keto-PGF1 alpha in untreated hypertensive subjects suggests that enhanced vessel wall prostacyclin synthesis may be a protective mechanism to prevent organ damage. As blood pressure is controlled this increase is no longer needed, and prostacyclin generation returns to normal.

Topics: Administration, Oral; Adult; Aged; Blood Pressure; Ethanolamines; Hemodynamics; Humans; Hypertension; Labetalol; Male; Middle Aged; Prostaglandins F; Thromboxane B2

This study investigated the effects of the peroxisome proliferator-activated receptor alpha (PPAR-α) agonist, Fenofibrate, on the secretion of vascular endothelial contraction factors in hypertensive rats to elucidate its possible mechanisms. The vascular ring contraction experiment was used to observe whether rat vascular tension of clean grade spontaneously hypertensive rats (SHR) changes after 1-h incubation of 0.1, 1.0, 10.0 μM Fenofibrate with 10.0 μM Fenofibrate, a PPAR-α antagonist (MK866), and a PPAR-γ antagonist (GW9662) in SHR. The results were compared with Wistar Kyoto rats. Enzyme-linked immunosorbent assay was used to detect the secretion of the serum vascular endothelial contraction factor prostacyclin-1α (PGF-1α), PGF-2α, and thromboxane B2 (TXB2). Western blot was used to detect COX-1 protein expression. A quantity of 10.0 μM Fenofibrate significantly reduced vasoconstriction in SHR compared to the control group (P = 0.013). The PPAR-α antagonist, MK866, significantly improved the vascular contractility of SHR when incubated with 10.0 μM Fenofibrate (P = 0.021). The PPAR-γ antagonist, GW9662, had no significant effect on the vascular contractility of SHR when incubated with 10.0 μM Fenofibrate (P = 0.071). The isolated aorta of SHR released significantly lower PGF- 1α (P = 0.014), PGF-2α (P = 0.023), and TXB2 (P = 0.017) levels in the 10.0 μM Fenofibrate group compared to the control group. COX-1 expression of SHR rat vascular endothelium was significantly depressed in the 10.0 μM Fenofibrate group compared to the control group (P = 0.027). In conclusion, Fenofibrate reduces the secretion of vascular endothelial contraction factors in hypertensive rats, which might arise through the endothelium influencing COX-1 expression.

Topics: Anilides; Animals; Aorta; Cyclooxygenase 1; Dinoprost; Dose-Response Relationship, Drug; Endothelium, Vascular; Fenofibrate; Gene Expression; Hypertension; Hypolipidemic Agents; Male; Membrane Proteins; PPAR alpha; PPAR gamma; Prostaglandins F; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Thromboxane B2; Tissue Culture Techniques; Vasoconstriction

To investigate the effect of two types of dietary protein on blood pressure, liver fatty acid desaturation and composition, and urine 6-keto-prostaglandin-F (PGF(1alpha)) level, the metabolite of prostacyclin.. 5-wk-old spontaneously hypertensive rats were fed 20% casein or purified fish protein. The fat source was 5% ISIO oil, which contains 47.9% (omega-6) and 1.7% (omega-3) total polyunsaturated fatty acids. After 2 mo on the diet, systolic blood pressure was reduced with fish protein compared with casein (189.8 +/- 10.5 versus 220.7 +/- 8.7).. Excretion of 6-keto-PGF(1alpha) in urine was negatively correlated with blood pressure. Liver cholesterol and phospholipid concentrations were 1.71- and 1.27-fold lower with fish protein than with casein, respectively. The fish protein diet lowered the 20:4(omega-6) proportion and the ratio of 20:4(omega-6) to 18:2(omega-6) in liver microsomal lipids and phospholipids, which was due to the reduced microsomal Delta6(omega-6) desaturation activity. Dietary protein source did not affect omega-3 fatty acid composition, and this was associated with a similar activation of Delta6(omega-3) desaturation in liver microsomes.. The present data indicated a significant blood pressure-lowering effect caused by fish protein, rather than by casein, that modified the fatty acid composition of liver phospholipids and liver microsomal total lipids.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Antihypertensive Agents; Blood Pressure; Body Weight; Caseins; Dietary Fats, Unsaturated; Dietary Proteins; Fatty Acid Desaturases; Fatty Acids, Unsaturated; Fish Proteins; Hypertension; Lipid Metabolism; Lipids; Liver; Male; Microsomes, Liver; Organ Size; Prostaglandins F; Rats; Rats, Inbred SHR

This study is aimed at evaluating the influence of the cytochrome P450 arachidonate metabolites on the renal alterations exhibited by the Lyon hypertensive (LH) rat. To that purpose, kidneys were isolated from LH rats and their normotensive (LN) controls and single-pass perfused at different pressure levels before (control conditions) and after cytochrome P450 inhibition by 7-ethoxyresorufin (7-ER, 1 microM). In control conditions, LH kidneys differed from LN ones by an increased preglomerular resistance and a blunted pressure natriuresis. 7-ER, which did not affect the function of LN kidneys, decreased the vascular resistance of LH kidneys, increased their glomerular filtration rate but had no effect on their pressure natriuresis. These results indicate that the renal cytochrome P450 arachidonate metabolism differs between LN and LH rats and is presumably involved in the functional alterations exhibited by LH kidneys.

Topics: Animals; Arachidonic Acid; Cyclic GMP; Cytochrome P-450 Enzyme System; Dose-Response Relationship, Drug; Glomerular Filtration Rate; Hypertension; In Vitro Techniques; Kidney; Kidney Function Tests; Male; Prostaglandins F; Rats; Renal Circulation; Sodium; Thromboxane B2

In human and experimental hypertension, flow (shear stress)-induced dilation in large arteries is attenuated and resistant to nitric oxide blockade. We tested the hypothesis that a defect in nitric oxide-and/or prostaglandin-dependent flow-induced dilation might occur in mesenteric resistance arteries from spontaneously hypertensive rats (SHR). We measured resistance mesenteric artery diameter in situ by intravital microscopy and simultaneously measured mesenteric arterial pressure in a collateral artery. The flow-diameter-pressure relationship was established in normotensive Wistar-Kyoto rats (WKY) and in SHR under control conditions and after endothelium removal, inhibition of nitric oxide synthesis with N omega-nitro-L-arginine methyl ester (10 micromol/L), or inhibition of prostaglandin synthesis with indomethacin (10 micromol/L). Production of prostaglandins was determined in the perfusate. Endothelium removal decreased artery diameter by 14 +/- 1.6% in WKY and 5 +/- 0.5% (P<.01 versus WKY) in SHR at a flow rate of 400 microL/min. In WKY, N omega-nitro-L-arginine methyl ester and indomethacin decreased resistance artery diameter by 12 +/- 3% (P<.001) and 5 +/- 2% (P<.01), respectively, at a flow rate of 400 microL/min; neither substance had any significant effect in SHR. In both strains, flow induced the production of 6-keto-prostaglandin F1alpha, the metabolite of prostacyclin; prostaglandin F2alpha; and thromboxane B2, the stable metabolite of thromboxane A2. Production of 6-keto-prostaglandin F1alpha and prostaglandin F2alpha was significantly lower in SHR than WKY, and TxB2 production was significantly higher in SHR than WKY. The present findings suggest that in SHR mesenteric resistance arteries, dilation in response to increases in flow was resistant to nitric oxide and prostaglandin synthesis blockade. A modification of the ratio of vasodilator to vasoconstrictor prostaglandins might be at least partly responsible for the decreased dilator response to flow in SHR.

Topics: Animals; Dinoprost; Hypertension; Mesenteric Arteries; Nitric Oxide; Prostaglandins; Prostaglandins F; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Regional Blood Flow; Thromboxane B2; Vascular Resistance

Enalapril produces an inhibition of the angiotensin-renin system, correlating the pre-therapy plasmatic renin activity with blood pressure decrease, during its administration. This does not always happen, data to the contrary existing in literature, suggesting that there are some other acting mechanisms. We studied 34 hypertensive patients, whose blood pressure levels were controlled by Enalapril at a mean dosage of 12.32 +/- 0.9. Determining plasmatic concentration of 6-keto PGF1a (a prostacyclin metabolite), T x B2 (a thromboxane A2 metabolite), their distribution, plasmatic renin activity and a radiological and biochemical study. We found a significant increase in their distribution and plasmatic renin at the end of the essay. The results suggest a possible double active mechanism: angiotension-renin and prostaglandins systems, owing to the imbalance occurring between prostacyclin and thromboxane, the first named being the most favoured. This, together with easy application and the lack of side effects, made this drug useful for treatment of blood hypertension.

Topics: Adolescent; Adult; Aged; Enalapril; Epoprostenol; Female; Humans; Hypertension; Male; Middle Aged; Prostaglandins F; Renin-Angiotensin System; Thromboxane B2; Time Factors

Increased mean arterial pressure during the aortic crossclamp period while on cardiopulmonary bypass was usually treated by us with hypotensive drugs. We noticed, however, that aspirating shed excess pulmonary venous blood from the open pleural cavities causes an immediate reduction in mean arterial pressure, obviating the need for any further pharmaceutical intervention. In this study we investigated the relationship between the reduction in mean arterial pressure and the levels of prostacyclin and prostaglandin E2 in the peripheral and pulmonary venous blood. Ten men undergoing coronary bypass operations had 21 episodes of increased mean arterial pressure (106.9 +/- 11.4 mm Hg) during aortic crossclamping, which was reduced to 67.4 +/- 11.4 mm Hg (p less than 0.001) only by aspirating a mean of 490 ml (range 150 to 1100 ml) of pulmonary venous blood from the pleurae back into the circulation. Mean peripheral prostacyclin level, measured as 6-keto-prostaglandin F1 alpha, and prostaglandin E2 level, both measured by radioimmunoassay technique, were significantly lower at peak mean arterial pressure (419 +/- 180 and 59.5 +/- 21.2 pg/ml) than at lowest mean arterial pressure (632 +/- 271 and 96.7 +/- 52.4 pg/ml for 6-keto-prostaglandin F1 alpha and prostaglandin E2, respectively; p less than 0.001). Prostaglandin F1 alpha and prostaglandin E2 levels in the aspirated pulmonary venous blood were 2309 +/- 3098 pg/ml and 749 +/- 909 pg/ml, respectively. The hypotensive effect of shed pulmonary venous blood that is aspirated back from the pleurae into the circulation seems to be mediated by the high levels of prostacyclin and prostaglandin E2, both powerful vasodilators.

Topics: Aged; Cardiopulmonary Bypass; Coronary Artery Bypass; Dinoprostone; Epoprostenol; Humans; Hypertension; Male; Middle Aged; Prostaglandins F; Radioimmunoassay; Suction

Streptozotocin diabetes in rats was complicated by spontaneous hypertension (SHR) and myocardial infarction (MIC), considered as "risk groups". Renal function was assessed on the basis of blood urea nitrogen (BUN) and albuminuria. BUN increased by 36% in Wistar diabetic group, by 100% in SHR + diabetes, and by 51% in MIR + diabetes. Morphologic changes were assessed by estimation of PAS-positive glycosaminoglycans and measurement of vascular wall thickness of glomerular arterioles. The risk groups showed exaggerated tendency for development of diabetic angiopathy. A significant imbalance between TXA2 and prostacyclin was found, which was reflected by TXB2/6-keto-PGF1 alpha (the stable metabolites of TXA2 and prostacyclin, respectively) ratio, which increased by 38% in Wistar diabetic rats, by 61% in SHR + diabetes, and by 133% in MIR + diabetes. These changes correlated very well with increased platelet aggregability (r = 0.70; p less than 0.05) and with increased lipid peroxide level (r = 0.60; p less than 0.05), but neither with total plasma cholesterol (r = 0.20), nor with plasma triglycerides (r = 0.34). Lipid peroxides increased 5-fold in Wistar diabetic rats, 6-fold in SHR + diabetes, and 5.5-fold in MIR + diabetes. A causative relationship between TXA2/PGI2 imbalance and lipid peroxide changes on one hand, and diabetic angiopathy, on the other, was suggested.

Topics: Animals; Blood Vessels; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Hypertension; Kidney; Lipid Peroxides; Lipids; Male; Myocardial Infarction; Pancreas; Platelet Aggregation; Prostaglandins F; Rats; Rats, Inbred SHR; Rats, Inbred Strains; Thromboxane B2

Topics: Arteriosclerosis; Female; Humans; Hypertension; Lipid Peroxides; Male; Middle Aged; Prostaglandins F; Vitamin E

To determine the influence of captopril on prostaglandins, the levels of plasma 6-keto-PGF1 alpha and thromboxane B2, the stable products of prostacyclin and thromboxane A2, respectively, were measured in 9 essential hypertensive subjects by radioimmunoassay before, 1 hour after a single oral 25 mg dose of captopril, and 2 weeks after administration of oral 25 mg captopril twice daily. A significant increase in plasma 6-keto-PGF1 alpha levels occurred after 2 weeks (p less than 0.05), but after 1 hour the increment was not significant. Plasma thromboxane B2 remained unchanged. Mean blood pressure fell significantly (p less than 0.02 after 1 hour, p less than 0.005 after 2 weeks) and plasma renin activity increased significantly after both periods (p less than 0.01 after 1 hour, p less than 0.02 after 2 weeks). There was no significant correlation between changes in blood pressure and 6-keto-PGF1 alpha for either time period. These results suggest that the elevation of plasma 6-keto-PGF1 alpha by captopril therapy was not responsible for reducing blood pressure, while enhanced plasma prostacyclin as a chronic response may contribute to prevention of thrombotic disorders and organ damage.

Topics: Blood Pressure; Blood Urea Nitrogen; Captopril; Creatinine; Electrolytes; Epoprostenol; Female; Heart Rate; Humans; Hypertension; Male; Middle Aged; Prostaglandins F; Renin; Thromboxane B2

We examined in rats the effects of intraperitoneal angiotensin II (AII) infusion for 12 d on urinary excretion, plasma concentration, and in vitro release of prostaglandin (PG) E2 and 6-keto-PGF1 alpha, a PGI2 metabolite. AII at 200 ng/min increased systolic blood pressure (SBP) progressively from 125 +/- 3 to 170 +/- 9 mmHg (P less than 0.01) and elevated fluid intake and urine volume. Urinary 6-keto-PGF1 alpha excretion increased from 38 +/- 6 to 55 +/- 5 and 51 +/- 7 ng/d (P less than 0.05) on days 8 and 11, respectively, of AII infusion, but urinary PGE2 excretion did not change. Relative to a control value of 129 +/- 12 pg/ml in vehicle-infused (V) rats, arterial plasma 6-keto-PGF1 alpha concentration increased by 133% (P less than 0.01) with AII infusion. Aortic rings from AII-infused rats released more 6-keto-PGF1 alpha (68 +/- 7 ng/mg) during 15-min incubation in Krebs solution than did rings from V rats (40 +/- 3 ng/mg); release of PGE2, which was less than 1% of that of 6-keto-PGF1 alpha, was also increased. Slices of inner renal medulla from AII-infused rats released more 6-keto-PGF1 alpha (14 +/- 1 ng/mg) during incubation than did slices from V rats (8 +/- 1 ng/mg, P less than 0.05), but PGE2 release was not altered. In contrast, AII infusion did not alter release of 6-keto-PGF1 alpha or PGE2 from inferior vena cava segments or from renal cortex slices. Infusion of AII at 125 ng/min also increased SBP, plasma 6-keto-PGF1 alpha concentration, and in vitro release of 6-keto-PGF1 alpha from rings of aorta and renal inner medulla slices; at 75 ng/min AII had no effect. SBP on AII infusion day 11 correlated positively with both 6-keto-PGF1 alpha plasma concentration (r = 0.54) and net aortic ring release (r = 0.70) when data from all rats were combined. We conclude that augmentation of PGI2 production is a feature of AII-induced hypertension. The enhancement of PGI2 production may be an expression of nonspecific alteration in vascular structure and metabolic functions during AII-induced hypertension, as well as the result of a specific effect of the peptide on the arachidonate-prostaglandin system.

Topics: Angiotensin II; Animals; Aorta, Thoracic; Body Weight; Dinoprostone; Hypertension; Kidney; Kidney Concentrating Ability; Male; Prostaglandins; Prostaglandins E; Prostaglandins F; Rats; Rats, Inbred Strains; Systole; Vena Cava, Inferior

Lasix effects on diuresis, natriuresis and pulmonary and renal prostaglandin biosynthesis and catabolism were examined in spontaneously hypertensive rats (SHR) and normotensive Wistar rats (NTR). PGE2 and PGF2 biosynthesis from 14C-arachidonic acid, and 3H-PGF1 and PGE2 catabolism were measured in kidney and lung homogenates. Changes in PG metabolism were shown to be dependent on age, blood pressure and the time of lasix action. Decreased biosynthesis and increased catabolism were demonstrated for PGE2, and reverse changes were shown for the production and decay of PGF2 alpha. Reciprocal changes were demonstrated in renal and pulmonary PG metabolism, an evidence of inter-organ relationships between prostaglandin systems of the organs in question. SHRs and NTRs showed different response of renal and pulmonary PGs, natriuresis and diuresis to lasix administration.

Topics: Age Factors; Animals; Dinoprost; Dinoprostone; Furosemide; Hypertension; Kidney; Lung; Prostaglandins; Prostaglandins E; Prostaglandins F; Rats; Rats, Inbred Strains