THE ACTION OF CORTICOSTEROIDS ON THE RENAL EXCRETION AND UTILIZATION OF CITRIC ACID

1964 ◽  
Vol 46 (3) ◽  
pp. 414-420 ◽  
Author(s):  
Helge Laake ◽  
Erling Kruge Brodwall
Keyword(s):  
Citric Acid ◽  
Steroid Hormones ◽  
Renal Excretion ◽  
Anabolic Steroids ◽  
Inhibitory Effect ◽  
Renal Tissue ◽  
Tubular Reabsorption ◽  
Enzyme Systems ◽  
Acid Clearance ◽  
Tubular Lumen

ABSTRACT During treatment with steroid hormones the tubular reabsorption of citric acid (cit.) increases, and the endogenous citric acid clearance is reduced. This is attributed to increased diffusion of citric acid from the tubular lumen to the renal tissue. With simultaneous administration of corticosteroids and anabolic steroids the tubular reabsorption of citric acid becomes normal. Steroid hormones block the renal synthesis of cit. and the renal utilization of cit. becomes identical with the amount of cit. reabsorbed in the tubules. Blockade of the synthesis of cit. is attributed to the inhibitory effect of steroid hormones on enzyme systems.

CORRELATION BETWEEN ANTIDIURETIC HORMONE EFFECT AND THE RENAL EXCRETION OF MAGNESIUM AND CALCIUM IN MAN

1964 ◽  
Vol 45 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Bent Nielsen
Keyword(s):  
Antidiuretic Hormone ◽  
Arginine Vasopressin ◽  
Renal Excretion ◽  
Normal Subjects ◽  
Inhibitory Effect ◽  
Tubular Reabsorption ◽  
Hormone Effect ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular ◽  
Most Probable Explanation

ABSTRACT The effect of injection of physiological doses of commercial preparations of lysine- or arginine-vasopressin on the renal excretion of magnesium and calcium was studied in 20 hydrated normal subjects. In the majority of the experiments the injections were followed by a rise in the rate of excretion of magnesium as well as of calcium. In 3 subjects endogenously induced antidiuresis produced similar effects. In 1 case no changes were revealed during antidiuresis. The most probable explanation of these results would seem to be that the antidiuretic hormone exerts an inhibitory effect on the renal tubular reabsorption of magnesium and calcium.

Renal effects of nitric oxide synthesis inhibition in cirrhotic rats

1994 ◽  
Vol 267 (6) ◽  
pp. R1454-R1460 ◽  
Author(s):  
N. M. Atucha ◽  
J. Garcia-Estan ◽  
A. Ramirez ◽  
M. C. Perez ◽  
T. Quesada ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Renal Excretion ◽  
Renal Plasma Flow ◽  
Tubular Reabsorption ◽  
Nitric Oxide Synthesis ◽  
Important Mediator ◽  
Experimental Liver Cirrhosis ◽  
Endogenous Nitric Oxide ◽  
And Control ◽  
Experimental Liver

In the present study, we have characterized the renal response to inhibition of endogenous nitric oxide (NO) synthesis [intravenous NG-nitro-L-arginine methyl ester (L-NAME) for 3 h] in anesthetized cirrhotic rats, with (ASC) and without (CIR) ascites, at doses that do not change blood pressure (BP). Administration of L-NAME induced opposite effects on water (UV) and sodium (UNaV) excretion in cirrhotic and control animals. Infusion of 1 microgram.kg-1.min-1 of L-NAME in CIR (n = 5) decreased renal plasma flow (RPF) at the end of the 3-h period, whereas UV, UNaV, and glomerular filtration rate (GFR) were unaltered. In contrast, infusion of L-NAME at 10 micrograms.kg-1.min-1 in six more CIR increased UV and UNaV significantly by the 1st h, without changes in BP or GFR, and these parameters remained elevated throughout the experiment. Infusion of 1 microgram.kg-1.min-1 in ASC (n = 6) did not change BP or GFR but significantly enhanced UV and UNaV after the 1st h. These effects were prevented by pretreatment with L-arginine (0.1 mg.kg-1.min-1) in another group of ASC infused with 1 microgram.kg-1.min-1 of L-NAME. These results indicate that, in ASC and CIR cirrhotic rats, inhibition of NO synthesis at nonpressor does improves renal excretion of sodium and water via a decrease in tubular reabsorption. NO is an important mediator of the renal excretory and hemodynamic alterations of experimental liver cirrhosis.

Renal excretion of cephapirin and cephaloridine: Evidence for saturable tubular reabsorption

1979 ◽  
Vol 25 (6) ◽  
pp. 870-876 ◽  
Author(s):  
Annie Arvidsson ◽  
Olof Borgå ◽  
Gunnár Alvan
Keyword(s):  
Renal Excretion ◽  
Tubular Reabsorption

Renal excretion of radiofluoride in the dog

1960 ◽  
Vol 198 (4) ◽  
pp. 829-832 ◽  
Author(s):  
Curtis H. Carlson ◽  
W. D. Armstrong ◽  
Leon Singer ◽  
Lerner B. Hinshaw
Keyword(s):  
Plasma Concentration ◽  
Glomerular Filtration ◽  
Renal Excretion ◽  
Urine Volume ◽  
Urine Concentration ◽  
Tubular Reabsorption ◽  
Carrier Free ◽  
Renal Clearances ◽  
Concentration Ratios

Renal clearances of continuously infused radiofluoride were measured in 10 dogs in which a large part of the skeleton had been excluded from the system in order to produce a more constant plasma radiofluoride concentration. The results were evaluated to describe the factors of glomerular filtration and tubular reabsorption of fluoride under several conditions. The animals that received carrier-free radiofluoride infusions excreted urine with a mean radiofluoride concentration 3.4–14.5 times that of the plasma. The urine-to-plasma concentration ratios obtained with animals given a load of stable fluoride was 13.5–29.6. An increased urine volume resulted in a decreased tubular reabsorption of fluoride and the clearance was increased. Chlorothiazide increased radiofluoride excretion but decreased the urine concentration. The radiofluoride clearances were always less than the creatinine clearances but were 7.8–179 times the chloride clearances. The effect of chlorothiazide was to decrease the ratio of fluoride to chloride clearance by increasing chloride clearance more than fluoride clearance.

Dissociation of Na-K-ATPase specific activity and net reabsorption of sodium

1975 ◽  
Vol 228 (6) ◽  
pp. 1745-1749 ◽  
Author(s):  
KA Fisher ◽  
LG Welt ◽  
JP Hayslett
Keyword(s):  
Enzyme Activity ◽  
Renal Cortex ◽  
Specific Activity ◽  
Specific Effect ◽  
Renal Tissue ◽  
Tubular Reabsorption ◽  
Sodium Absorption ◽  
Sodium Reabsorption ◽  
Base Line ◽  
Outer Medulla

Prevoius studies have suggested that the increase in specific activity of Na-K-ATPase in renal tissue during treatment with glucocorticoids occurred as a result of aconcurrent rise in net tubular reabsorption of sodium. Since recent data have indicated a specific effect of glucocortiocoids on epithelial cells, experiments were performed to determine whether enzyme activity and net sodium reabsorption could be dissociated.Evidence is provided demonstrating that base-line specific activity of Na-K-ATPase in rat renal cortex and outer medulla does not correlate directly with net sodium reabsorption since enzyme activity did not change after a chronic reduction in glomerularfiltration rate and the rate of sodium reabsorption. Further studies showed a markedrise in Na-K-ATPase after 4 days of treatment with methylprednisolone despite a fall in sodium absorption. These results suggest a direct effect of glucocorticoids onrenal Na-K-ATPase and illistrate the difficulty in assigning a transport role tothis enzyme from the correlation of specific activity with rates of net electrolyte transport.

THE RELATIONSHIP BETWEEN NUTRITION AND ANDROGENIC ACTIVITY IN PUBESCENT TWIN CALVES, AND THE EFFECT OF ORCHITIS

1967 ◽  
Vol 38 (4) ◽  
pp. 455-NP ◽  
Author(s):  
T. MANN ◽  
L. E. A. ROWSON ◽  
R. V. SHORT ◽  
J. D. SKINNER
Keyword(s):  
Citric Acid ◽  
Control Animal ◽  
Inhibitory Effect ◽  
Seminal Vesicles ◽  
The Other ◽  
Identical Twin ◽  
Androgen Deficiency ◽  
Androgenic Activity ◽  
The Relationship

SUMMARY The inhibitory effect of underfeeding on the process of male pubescence was studied in three pairs of bovine identical twin calves by feeding one twin on a normal and the other on a low plane of nutrition. As a result of malnutrition the development of the androgenic function of the testes was retarded much more markedly than spermatogenesis. In the undernourished twin the testes contained and secreted less testosterone, and showed a lower testosterone: androstenedione ratio, than in the control animal. This nutritionally conditioned androgen deficiency was clearly reflected in a markedly retarded onset of production of fructose and citric acid by the seminal vesicles. After castration the underfed twin responded to testosterone injections much more sluggishly than the control twin, as shown by the delayed appearance of fructose and citric acid in electrically-induced ejaculates. Observations were also made on the effects of orchitis and cryptorchidism. Both these conditions lowered markedly the androgenic activity in the calves.

Citric Acid Enhances the Antithrombotic Effect of Aspirin in Many Aspirin-Resistant Subjects

1997 ◽  
Vol 3 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Svetlana Kaplan ◽  
Alexander Kaplan ◽  
Karen F. Marcoe ◽  
William P. Hammond ◽  
Lloyd D. Fisher ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Citric Acid ◽  
Poor Response ◽  
Inhibitory Effect ◽  
Consecutive Series ◽  
Double Blind ◽  
Platelet Aggregometry ◽  
Antithrombotic Medication ◽  
Average Drop ◽  
Apparently Healthy

This study had three objectives: (1) to determine the frequency of high platelet aggregators in a consecutive series of 268 apparently healthy volunteers who presented to our Center; (2) to assess the inhibitory effect of aspirin (ASA) on these high aggregators; (3) to determine, in a double-blind trial, whether or not the addition of citric acid (CTA) to ASA would increase its inhibitory effect in subjects who had a suboptimal response to aspirin alone. A platelet aggregation-scoring methodology developed for turbidimetric platelet aggregometry was used to quantify baseline aggregation and medicinal effects. We define a high aggregator as one whose unmedicated PA score is ≥30. We define the response of a high aggregator to ASA as poor if the medicated PA score stays at ≥30. We found that 58 of 268 apparently healthy unmedicated volunteers (22%) had PA scores ≥30. and that 27 of these (47%) had a poor response to 325 mg ASA, with an average drop in their PA scores from 49.5 ± 13.1 to 41.1 ± 8.6 (16%). Twenty-five of these 27 people were enrolled in the double-Mind study comparing the effect of ASA and ASA + CTA on platelet aggregability. Of these high aggregators who had a poor response to ASA, 12 of 25 (50%) had a good response to 162.5 mg of ASA plus 162.5 mg of CTA, with an average drop of their PA scores from 46.7 ± 13.2 to 22.0 ± 5.2 (53%). CTA alone had no effect on the PA score, which was similar to the control placebo. Our data suggest that a 1:1 combination of ASA and CTA may offer significantly greater protection agairtst arterial thrombotic events than ASA alone in subjects who respond poorly to ASA. Key Words: Platelet aggregation—Antithrombotic medication—Thrombosis.

Capsazepine inhibits cough induced by capsaicin and citric acid but not by hypertonic saline in guinea pigs

1995 ◽  
Vol 79 (4) ◽  
pp. 1082-1087 ◽  
Author(s):  
U. G. Lalloo ◽  
A. J. Fox ◽  
M. G. Belvisi ◽  
K. F. Chung ◽  
P. J. Barnes
Keyword(s):  
Citric Acid ◽  
Hypertonic Saline ◽  
Guinea Pigs ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
Sensory Nerves ◽  
Cough Reflex ◽  
Acidic Solutions ◽  
Nasal Irritation ◽  
Cough Response

Acidic solutions mimick many of the effects of capsaicin (Cap), including pain, bronchoconstriction, cough, and sensory neuropeptide release. Evidence from the use of the Cap antagonist capsazepine suggests that in some cases protons act at the Cap receptor. In the present study, we have investigated whether cough evoked by Cap and citric acid (CA) is mediated specifically via the Cap receptor on airway sensory nerves. We have examined the effects of capsazepine on Cap-, CA-, and hypertonic saline-induced cough and also on CA-induced nasal irritation in awake guinea pigs. Capsazepine was nebulized for 5 min before cough challenges with Cap for 5 min and CA for 10 min. Control animals were pretreated with vehicle alone. Capsazepine (100 microM) inhibited the cough response to 30 microM Cap from 0.77 +/- 0.14 coughs/min in control animals to 0.23 +/- 0.08 coughs/min (P < 0.05) and to 80 microM Cap from 1.4 +/- 0.23 to 0.3 +/- 0.11 coughs/min (P < 0.01). There was no effect, however, of lower concentrations of capsazepine (5 and 10 microM) against Cap-evoked cough. At a concentration of 100 microM, capsazepine also inhibited the coughing induced by 0.25 M CA from 1.8 +/- 0.26 to 0.93 +/- 0.31 coughs/min (P < 0.05) but not that induced by 0.5 M CA. Nasal irritation induced by 0.25 M CA, but not by 0.5 M CA, was also inhibited by capsazepine from 2.47 +/- 0.37 to 0.75 +/- 0.31 nose wipes/min (P < 0.05). This inhibitory effect of capsazepine did not appear to reflect a nonspecific suppression of the cough reflex, since cough evoked by exposure to hypertonic (7%) saline for 10 min was unaffected by pretreatment with capsazepine (100 microM). These data show that capsazepine is a specific inhibitor of Cap- and CA-induced cough in guinea pigs. Moreover, they suggest that low pH stimuli evoke cough and nasal irritation by an action at the Cap receptor, either directly or through the release of an intermediate agent.

scholarly journals THE RELATIONSHIP OF HYDROGEN PEROXIDE TO THE INHIBITION OF THE GLYOXALASE ACTIVITY OF INTACT ERYTHROCYTES BY X-RADIATION

1958 ◽  
Vol 41 (4) ◽  
pp. 737-753 ◽  
Author(s):  
S. J. Klebanoff
Keyword(s):  
Hydrogen Peroxide ◽  
Plasma Glucose ◽  
Physiological Saline ◽  
Inhibitory Effect ◽  
Enzyme Systems ◽  
Low Concentrations ◽  
X Irradiation ◽  
Ionizing Radiations ◽  
Relationship Of

The x-irradiation of a dilute suspension of erythrocytes results in a decrease in the glyoxalase activity of the cells as a result of a fall in the reduced glutathione level. The present paper deals with the possible role of H2O2 in this reaction. The addition of intact erythrocytes to physiological saline previously irradiated with 150,000 r or 225,000 r results in a fall in the glyoxalase activity of the cells. The inhibition is prevented by the preincubation of the irradiated saline with catalase and is reversed by the addition of plasma, glucose, adenosine, and inosine to the cell suspension. An inhibition of the glyoxalase activity is also produced by the addition of H2O2 to the suspension of erythrocytes. The inhibitory effect of H2O2 can be prevented and largely reversed by plasma, glucose, adenosine, and inosine. Methylglyoxal is also protective under these conditions. Hydrogen peroxide formed continuously and in low concentrations by enzyme systems appears to be more effective than added H2O2 in inhibiting the glyoxalase system. The inhibition by H2O2-producing enzyme systems is minimized by the addition of catalase, plasma, glucose, methylglyoxal, and to a lesser extent, by adenosine and inosine, and is accentuated by the addition of sodium azide. The results are discussed in relation to the role of H2O2 and catalase in the toxicity of ionizing radiations.

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