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G C Agnoli R Borgatti M Cacciari S Dorigoni C Garutti E Ikonomu P Lenzi M Marinelli 《Bollettino della Società italiana di biologia sperimentale》1989,65(2):163-169
The renal function was evaluated by clearance (cl.) method during hypotonic polyuria and successive relative antidiuresis induced by lysine-8-vasopressin administration. Four 15 min and two 60 min cl. periods were performed in hypotonic polyuria and antidiuresis, respectively. Glomerular filtration rate was estimated by creatinine cl., the osmotic cl. (Cosm' CH2O), the absolute and fractional excretions of water, sodium, potassium and chloride were determined by usual methods. The urinary PGE2, 6-keto-PGF1 alpha and TxB2 excretions were determined by RIA method. The study protocol was applied on 14 healthy women in acute potassium depletion, treated with indomethacin (100 mg i.m. at the end of the oral water load). In Group D3 (n = 6) in the presence of a greater potassium cumulative deficit (198.4 +/- 22.2 meq), in hypotonic polyuria, indomethacin induces significant effects as an increase of fractional hydro-electrolytic reabsorptions and as a decrease of urinary prostanoid excretion. The indomethacin tubular action in potassium depletion differs significantly from that observed in normal potassium balance. 相似文献
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G C Agnoli R Borgatti M Cacciari S Dorigoni C Garutti E Ikonomu P Lenzi M Marinelli 《Bollettino della Società italiana di biologia sperimentale》1989,65(2):155-161
The renal function was evaluated by clearance (cl.) method during hypotonic polyuria and successive relative antidiuresis induced by lysine-8-vasopressin (LVP) administration. Four 15 min and two 60 min cl. periods were performed during hypotonic polyuria and antidiuresis, respectively. Glomerular filtration rate was estimated by creatinine cl.; the osmotic cl. (Cosm'CH2O), the absolute and fractional excretions of water, sodium, potassium and chloride were determined by usual methods. The urinary PGE2, 6-keto-(-)PGF1 alpha and TxB2 concentrations were determined by RIA method. The study protocol was applied on 22 healthy women in acute potassium depletion obtained by natriuretic treatment combined with replacement on quantitative basis of net salt and water urinary losses either in normal potassium diet intake (50 meq/d) or in a low one (less than or equal to 10 meq/d). In Group D3 (n = 6) in the presence of a greater potassium cumulative deficit (198.4 +/- 22.2 meq), as compared to normal potassium balance, a significant reduction of kaliemia and a significant increase of PRA were present. During hypotonic poliuria, besides a marked renal potassium conservation, a significant decrease of creatinine cl., fractional chloride reabsorption (apparently at the diluting segments) and of urinary 6KPGF and TxB2 excretions, were observed. Urinary PGE2 excretion was n.s. reduced. 相似文献
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G C Agnoli R Borgatti M Cacciari S Dorigoni C Garutti E Ikonomu P Lenzi M Marinelli 《Bollettino della Società italiana di biologia sperimentale》1989,65(2):147-153
The renal function was studied by clearance (cl.) method during hypotonic polyuria (oral water load followed by 5% dextrose solution infusion) and successive relative antidiuresis induced by lysine-8-vasopressin (LVP) administration (5 microU in bolo followed by continuous infusion at a rate of 0.04 microU/min). Four 15 min and two 60 min clearance (cl.) periods were performed during hypotonic polyuria and antidiuresis, respectively. Glomerular filtration rate was estimated by creatinine cl.; the osmotic cl. (Cosm, CH2O), the absolute and fractional excretions of water, sodium, potassium and chloride were determined by usual methods. The urinary PGE2, 6-keto-PGF1 alpha and TxB2 concentrations were determined by RIA method. Fourteen healthy women submitted to a normal sodium and potassium daily intake were studied; in 6 of them paired studies in absence and in presence of indomethacin (100 mg, i.m.), respectively, were performed. LVP induced a significant reduction of creatinine cl., urinary flow rate and of prostanoid excretion. In hypotonic polyuria, indomethacin significantly reduced the creatinine cl. and the diuretic response to the water load; moreover the urinary PGE2 and 6-keto-PGF1 alpha excretions were significantly lower (85.6 +/- 1.9% and 37.7 +/- 3.2%) while the reduction of urinary TxB2 excretion was not significant (34.4 +/- 13%). Indomethacin did not affect significantly the LVP renal effects in normal potassium balance. 相似文献
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William G Schrage Niki M Dietz Michael J Joyner 《Journal of applied physiology》2006,100(5):1506-1512
ATP-sensitive potassium (KATP) channels have been suggested to contribute to coronary and skeletal muscle vasodilation during exercise, either alone or interacting in a parallel or redundant process with nitric oxide (NO), prostaglandins (PGs), and adenosine. We tested the hypothesis that KATP channels, alone or in combination with NO and PGs, regulate exercise hyperemia in forearm muscle. Eighteen healthy young adults performed 20 min of moderate dynamic forearm exercise, with forearm blood flow (FBF) measured via Doppler ultrasound. After steady-state FBF was achieved for 5 min (saline control), the KATP inhibitor glibenclamide (Glib) was infused into the brachial artery for 5 min (10 microg.dl(-1).min(-1)), followed by saline infusion during the final 10 min of exercise (n = 9). Exercise increased FBF from 71 +/- 11 to 239 +/- 24 ml/min, and FBF was not altered by 5 min of Glib. Systemic plasma Glib levels were above the therapeutic range, and Glib increased insulin levels by approximately 50%, whereas blood glucose was unchanged (88 +/- 2 vs. 90 +/- 2 mg/dl). In nine additional subjects, Glib was followed by combined infusion of NG-nitro-L-arginine methyl ester (L-NAME) plus ketorolac (to inhibit NO and PGs, respectively). As above, Glib had no effect on FBF but addition of L-NAME + ketorolac (i.e., triple blockade) reduced FBF by approximately 15% below steady-state exercise levels in seven of nine subjects. Interestingly, triple blockade in two subjects caused FBF to transiently and dramatically decrease. This was followed by an acute recovery of flow above steady-state exercise values. We conclude 1) opening of KATP channels is not obligatory for forearm exercise hyperemia, and 2) triple blockade of NO, PGs, and KATP channels does not reduce hyperemia more than the inhibition of NO and PGs in most subjects. However, some subjects are sensitive to triple blockade, but they are able to restore FBF acutely during exercise. Future studies are required to determine the nature of these compensatory mechanisms in the affected individuals. 相似文献
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A short (75-110 min) mild (39.5 degrees C) whole body hyperthermia of humans does not alter the absolute amount of peripheral lymphocytes immediately after heating, but significantly reduces their relative amount due to neutrophil increase. Body heating does not induce lymphocyte degeneration: their potential viability does not reduce. The total level of lymphocyte oxidative metabolism remains unaltered, while SDG and LDG activities are seen reduced and increased, respectively. Lymphocytes adapt to body heating by inducing thermotolerant state and activating anaerobic metabolism. 相似文献
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Crecelius AR Kirby BS Richards JC Garcia LJ Voyles WF Larson DG Luckasen GJ Dinenno FA 《American journal of physiology. Heart and circulatory physiology》2011,301(4):H1302-H1310
ATP is an endothelium-dependent vasodilator, and findings regarding the underlying signaling mechanisms are equivocal. We sought to determine the independent and interactive roles of nitric oxide (NO) and vasodilating prostaglandins (PGs) in ATP-mediated vasodilation in young, healthy humans and determine whether any potential role was dependent on ATP dose or the timing of inhibition. In protocol 1 (n = 18), a dose-response curve to intrabrachial infusion of ATP was performed before and after both single and combined inhibition of NO synthase [N(G)-monomethyl-L-arginine (L-NMMA)] and cyclooxygenase (ketorolac). Forearm blood flow (FBF) was measured via venous occlusion plethysmography and forearm vascular conductance (FVC) was calculated. In this protocol, neither individual nor combined NO/PG inhibition had any effect on the vasodilatory response (P = 0.22-0.99). In protocol 2 (n = 16), we determined whether any possible contribution of both NO and PGs to ATP vasodilation was greater at low vs. high doses of ATP and whether inhibition during steady-state infusion of the respective dose of ATP impacted the dilation. FBF in this protocol was measured via Doppler ultrasound. In protocol 2, infusion of low (n = 8)- and high-dose (n = 8) ATP for 5 min evoked a significant increase in FVC above baseline (low = 198 ± 24%; high = 706 ± 79%). Infusion of L-NMMA and ketorolac together reduced steady-state FVC during both low- and high-dose ATP (P < 0.05), and in a subsequent trial with continuous NO/PG blockade, the vasodilator response from baseline to 5 min of steady-state infusion was similarly reduced for both low (ΔFVC = -31 ± 11%)- and high-dose ATP (ΔFVC -25 ± 11%; P = 0.70 low vs. high dose). Collectively, our findings indicate a potential modest role for NO and PGs in the vasodilatory response to exogenous ATP in the human forearm that does not appear to be dose or timing dependent; however, this is dependent on the method for assessing forearm vascular responses. Importantly, the majority of ATP-mediated vasodilation is independent of these putative endothelium-dependent pathways in humans. 相似文献
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Sangan P Brill SR Sangan S Forbush B Binder HJ 《The Journal of biological chemistry》2000,275(40):30813-30816
Active potassium absorption in the rat distal colon is electroneutral, Na(+)-independent, partially chloride-dependent, and energized by an apical membrane H,K-ATPase. Both dietary sodium and dietary potassium depletion substantially increase active potassium absorption. We have recently reported that sodium depletion up-regulates H,K-ATPase alpha-subunit mRNA and protein expression, whereas potassium depletion up-regulates H,K-ATPase beta-subunit mRNA and protein expression. Because overall potassium absorption is non-conductive, K-Cl cotransport (KCC) at the basolateral membrane may also be involved in potassium absorption. Although KCC1 has not been cloned from the colon, we established, in Northern blot analysis with mRNA from the rat distal colon using rabbit kidney KCC1 cDNA as a probe, the presence of an expected size mRNA in the rat colon. This KCC1 mRNA is substantially increased by potassium depletion but only minimally by sodium depletion. KCC1-specific antibody identified a 155-kDa protein in rat colonic basolateral membrane. Potassium depletion but not sodium depletion resulted in an increase in KCC1 protein expression in basolateral membrane. The increase of colonic KCC1 mRNA abundance and KCC1 protein expression in potassium depletion of the rat colonic basolateral membrane suggests that K-Cl cotransporter: 1) is involved in transepithelial potassium absorption and 2) regulates the increase in potassium absorption induced by dietary potassium depletion. We conclude that active potassium absorption in the rat distal colon involves the coordinated regulation of both apical membrane H,K-ATPase and basolateral membrane KCC1 protein. 相似文献
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Infusion of 1 mg/kg per day of prostaglandin E(1) (PGE(1)) for 2 and 7 wk failed to correct the dermal signs of essential fatty acid (EFA) deficiency in rats despite the known conversion of EFA to certain prostaglandins. PGE(1) caused no significant changes in serum cholesterol, triglycerides, or phospholipids or in liver neutral lipids in EFA-deficient or normal rats. In normal rats epinephrine-induced lipolysis was greater in fat pads from infused than from untreated rats. The effect on epinephrine-induced lipolysis was greater after the 7 wk infusion than after the 2 wk infusion. The 7 wk infusion also lowered plasma free fatty acid (FFA) concentrations. Infusion of PGE(2) and PGF(2alpha) in combination for 4 wk had no significant effect on either dermal signs of EFA deficiency, lipolysis, or plasma FFA concentrations. 相似文献
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G C Agnoli R Borgatti M Cacciari E Ikonomu P Lenzi M Marinelli M Martello 《Bollettino della Società italiana di biologia sperimentale》1992,68(8-9):561-566
We have investigated the relative roles of angiotensin II on the renal function and urinary excretion of some prostanoids in healthy women submitted to different conditions of potassium balance. To this aim we have evaluated the effects of an acute inhibition of angiotensin converting enzyme by enalapril (E). The renal function was explored by clearance (cl.) method during induced hypotonic polyuria (oral water load followed by 5% dextrose solution infusion). During 60 min cl. period the urinary PGE2, 6-keto-PGF1 alpha and TxB2 were determined by RIA method. Each subject received paired studies, in absence and presence of E (10 mg administered per os 1 hour before the water load). Basal values of plasma renin activity (PRA) and urinary aldosterone (excreted during the 24 hours before the water load) were also determined by RIA method. This study protocol was applied in normal potassium balance (n = 6) and induced moderate potassium depletion (n = 6). This paper concerns the group in potassium depletion in both absence (D4) and presence of E (D4.E). Potassium depletion was induced by adaptation to a normal sodium (150 mmol/d) and low potassium (< or = 10 mmol/d) dietary intake combined to natriuretic treatment. The water and NaCl net losses were restored by 0.9% NaCl solution infusion. The cumulative potassium deficit achieved at the end of the depletive treatment was 214 +/- 54 mmol. This treatment induced significant decrease in basal plasma potassium concentration and increase in PRA without affecting urinary aldosterone and plasma sodium concentration.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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The role of prostaglandins in human parturition 总被引:1,自引:0,他引:1
S Lundin-Schiller M D Mitchell 《Prostaglandins, leukotrienes, and essential fatty acids》1990,39(1):1-10