In vivo Demonstration of Renal Carbonic Anhydrase Activity in the Fetal Lamb

Neonatology ◽  
1978 ◽  
Vol 34 (5-6) ◽  
pp. 253-258 ◽  
Author(s):  
Jean E. Robillard ◽  
Christine Sessions ◽  
Fred G. Smith, jr.
Keyword(s):  
Carbonic Anhydrase ◽  
Carbonic Anhydrase Activity ◽  
Fetal Lamb ◽  
Renal Carbonic Anhydrase

RENAL CARBONIC ANHYDRASE IN PREMATURE AND MATURE INFANTS

PEDIATRICS ◽  
1951 ◽  
Vol 7 (2) ◽  
pp. 182-185
Author(s):  
RICHARD DAY ◽  
JANE FRANKLIN
Keyword(s):  
Carbonic Anhydrase ◽  
Premature Infants ◽  
Carbonic Anhydrase Activity ◽  
Renal Carbonic Anhydrase

The carbonic anhydrase activity in the kidneys of premature infants was studied because it was thought that if the renal enzyme is as deficient as that in the blood, inefficiency in acidification of urine might result. In contrast with the blood, postmortem specimens of kidneys of premature infants were found to exhibit carbonic anhydrase activity similar to that found in the case of kidneys from older infants and adults.

Effects of Prolonged Administration of Diamox on Excretion of Acid and Carbonic Anhydrase and Glutaminase Activities in the Kidney

1957 ◽  
Vol 189 (3) ◽  
pp. 551-556 ◽  
Author(s):  
Donald W. Seldin ◽  
Floyd C. Rector ◽  
H. C. Teng
Keyword(s):  
Carbonic Anhydrase ◽  
Enzyme System ◽  
Chronic Administration ◽  
Carbonic Anhydrase Activity ◽  
Prolonged Administration ◽  
Urine Ph ◽  
Alkaline Urine ◽  
Titratable Acid ◽  
Load Effects ◽  
Renal Carbonic Anhydrase

Diamox inhibits renal carbonic anhydrase activity as effectively when given chronically as when given acutely. The persistently high urine ph, low titratable acid and high bicarbonate excretion in the urine of rats receiving Diamox chronically were the result of the alkaline load effects of sodium Diamox, rather than effects from the inhibition of carbonic anhydrase. The chronic administration of Diamox activated the renal glutaminase enzyme system, resulting in the excretion of normal or increased amounts of ammonia into an alkaline urine. The activation of glutaminase was potentiated by the restriction of dietary NaCl. An unexplained hypernatremia developed during the course of prolonged administration of Diamox.

scholarly journals The Carbonic Anhydrase Inhibitor Ethoxzolamide Inhibits the Mycobacterium tuberculosis PhoPR Regulon and Esx-1 Secretion and Attenuates Virulence

2015 ◽  
Vol 59 (8) ◽  
pp. 4436-4445 ◽  
Author(s):  
Benjamin K. Johnson ◽  
Christopher J. Colvin ◽  
David B. Needle ◽  
Felix Mba Medie ◽  
Patricia A. DiGiuseppe Champion ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Carbonic Anhydrase ◽  
Regulatory System ◽  
Carbonic Anhydrase Activity ◽  
Carbonic Anhydrase Inhibitor ◽  
Fluorescent Reporter ◽  
Content Type ◽  
Pathogen Virulence ◽  
Mutant Phenotypes

ABSTRACTMycobacterium tuberculosismust sense and adapt to host environmental cues to establish and maintain an infection. The two-component regulatory system PhoPR plays a central role in sensing and responding to acidic pH within the macrophage and is required forM. tuberculosisintracellular replication and growthin vivo. Therefore, the isolation of compounds that inhibit PhoPR-dependent adaptation may identify new antivirulence therapies to treat tuberculosis. Here, we report that the carbonic anhydrase inhibitor ethoxzolamide inhibits the PhoPR regulon and reduces pathogen virulence. We show that treatment ofM. tuberculosiswith ethoxzolamide recapitulatesphoPRmutant phenotypes, including downregulation of the core PhoPR regulon, altered accumulation of virulence-associated lipids, and inhibition of Esx-1 protein secretion. Quantitative single-cell imaging of a PhoPR-dependent fluorescent reporter strain demonstrates that ethoxzolamide inhibits PhoPR-regulated genes in infected macrophages and mouse lungs. Moreover, ethoxzolamide reducesM. tuberculosisgrowth in both macrophages and infected mice. Ethoxzolamide inhibitsM. tuberculosiscarbonic anhydrase activity, supporting a previously unrecognized link between carbonic anhydrase activity and PhoPR signaling. We propose that ethoxzolamide may be pursued as a new class of antivirulence therapy that functions by modulating expression of the PhoPR regulon and Esx-1-dependent virulence.

Renal carbonic anhydrase

1982 ◽  
Vol 243 (4) ◽  
pp. F311-F324 ◽  
Author(s):  
D. C. Dobyan ◽  
R. E. Bulger
Keyword(s):  
Carbonic Anhydrase ◽  
Collecting Duct ◽  
Mammalian Species ◽  
Carbonic Anhydrase Activity ◽  
The Body ◽  
Carbonic Anhydrases ◽  
Duct System ◽  
Renal Carbonic Anhydrase ◽  
Membrane Bound ◽  
Editorial Review

Carbonic anhydrase is a zinc metalloenzyme widely distributed throughout the tissues of the body. This enzyme exists in a number of isozymic forms in most mammalian species. Significant advances over the past decade have been made in characterizing the nature of renal carbonic anhydrase. In the kidney, this enzyme is thought to play a pivotal role in urinary acidification and bicarbonate reabsorption. Two distinct isozymes of carbonic anhydrase have now been identified in the mammalian kidney. A soluble cytoplasmic form, similar if not identical to human erythrocyte carbonic anhydrase C, accounts for the bulk of the renal carbonic anhydrase activity. In addition, a membrane-bound form constituting only about 2--5% of the renal activity has been found in the brush border and basolateral fractions of kidney homogenates. The histochemical and immunocytochemical localization of these isozymes along the nephron and collecting duct system of various mammalian species suggests that marked heterogeneity exists. The Editorial Review examines the biochemical and morphological approaches that have been used to elucidate the nature of renal carbonic anhydrase and to assess its distribution along the urinary tubule. Possible physiological roles for the renal carbonic anhydrases are considered for the different segments of the nephron and collecting duct system.

Kidney Glutaminase and Carbonic Anhydrase Activities and Renal Electrolyte Excretion in Rats

1955 ◽  
Vol 184 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Edward Muntwyler ◽  
Michael Iacobellis ◽  
Grace E. Griffin
Keyword(s):  
Carbonic Anhydrase ◽  
Ammonia Excretion ◽  
Titratable Acidity ◽  
Carbonic Anhydrase Activity ◽  
Chemical Compositions ◽  
Electrolyte Excretion ◽  
Urine Ph ◽  
K Deficiency ◽  
Renal Carbonic Anhydrase ◽  
Glutaminase Activity

The plasma electrolyte composition and 24-hour urine electrolyte excretion were determined in fasting normal, K-deficient and protein and K-deficient rats following the administration of equal molar quantities of NaCl, KCl, NH4Cl and KHCO3. An attempt was made to relate any differences in the compositions of the plasma and urine to the levels of renal glutaminase and carbonic anhydrase activities, and, to the chemical compositions of the skeletal muscle and kidneys. Renal glutaminase and carbonic anhydrase activities were found increased in K-deficiency and reduced in protein and K-deficiency. Significant changes from corresponding control levels of renal glutaminase were found in normal and K-deficient animals only after the administration of NH4Cl (increased), and, after the administration of KHCO3 (reduced). The only outstanding change of the carbonic anhydrase activity of the kidneys from these animals was a reduction following NH4Cl administration. The doubly deficient rats showed a significant increase in renal glutaminase activity after NH4Cl administration; on the other hand, KCl administration resulted in a further reduction of the lowered renal carbonic anhydrase activity. The experimental results supported the contention that a relationship exists between urinary ammonia excretion and the level of renal glutaminase activity, while the transfer of H+ to the urine and the level of renal carbonic anhydrase activity could not be related. No clear relationship was found between the K excretion and/or K content of the kidneys and the urine total titratable acidity and ammonia excretion, and urine ph.

scholarly journals Effect of NaHS on carbonic anhydrase activity of human erythrocyte

2016 ◽  
Vol 7 (3) ◽  
pp. 23-27 ◽  
Author(s):  
Abhijit Bhakta ◽  
Maitreyi Bandyopadhyay ◽  
Sayantan Dasgupta ◽  
Santanu Sen ◽  
Arun Kumar ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Normal Saline ◽  
Carbonic Anhydrase Activity ◽  
Experimental Models ◽  
Test Tube ◽  
Dependent Manner ◽  
Carbonic Anhydrases ◽  
Medical Sciences ◽  
First Time

Background: In contrast to its role as poison, hydrogen sulfide (H2S) is recently considered as a gaso-transmitter which mediates important physiologic functions in humans. Evidence is accumulating to demonstrate that inhibitors of H2S production or therapeutic H2S donor compounds exert significant effects in various experimental models. Carbonic anhydrases (CA) are a group of zinc-containing metalloenzymes that catalyse the reversible hydration of carbon dioxide. CAs activity in erythrocytes (CAI and CAII) has recently been observed to be associated with various pathological conditions especially in diabetes mellitus, hypertension and lipid disorders. Alteration of this enzyme activity has been reported by the effect of advanced glycation end products methylglyoxal and reduced glutathione.   Aims and Objectives: As H2S, being a mediator of many physiological functions and synthesized in vivo, may affect functions of many intracellular proteins like carbonic anhydrase, the objective of this study is to find out if there is any change in the carbonic anhydrase activity under the effect of H2S- donor NaHS in dose dependant manner using RBC model in vitro.Materials and Methods: Blood sample was collected from forty (40) numbers of healthy volunteers of 18-40 years of in heparin containing vials and packed cells were prepared immediately by centrifugation  The packed erythrocytes were washed three times with normal saline and  diluted (1:10) with the normal saline. One ml each of diluted packed cells was taken in eight test tubes. Serial dilutions of NaHS (1to 250 µMol/L) was added to all the test tubes except for the first test tube where only normal saline was added and   incubated at room temperature for one hour. Haemolysates was prepared from the erythrocytes with equal volume of distilled water in each tube and the CA activity was determined in the haemolysates using standardized method.Results: There is significant increase of CA activity in dose dependent manner under the effect of NaHS and also compared to the activity of hemolysate prepared without NaHS.  Conclusions:Our study for the first time demonstrated that the Carbonic Anhydrase activity of erythrocytes is significantly increases by the effect of NaHS and this study reveals some important biological role of H2S and carbonic anhydrase.Asian Journal of Medical Sciences Vol. 7(3) 2016 23-27

Direct evaluation of the permeability of the rat proximal convoluted tubule to CO2

1982 ◽  
Vol 242 (5) ◽  
pp. F470-F476
Author(s):  
M. S. Lucci ◽  
L. R. Pucacco ◽  
N. W. Carter ◽  
T. D. DuBose
Keyword(s):  
Carbonic Anhydrase ◽  
Proximal Tubule ◽  
Carbonic Acid ◽  
Carbonic Anhydrase Activity ◽  
Proximal Convoluted Tubule ◽  
Direct Evaluation ◽  
Carbon Dioxide Gas ◽  
Peritubular Capillaries ◽  
Rat Proximal Tubule

Conflicting data exist regarding the ability of the rat proximal convoluted tubule to maintain a transepithelial gradient for CO2 and the effects of carbonic anhydrase on CO2 permeability. The present in vivo microperfusion experiments were designed to assess the ability of the rat proximal tubule to sustain a CO2 gradient between tubule lumen and peritubular blood. Tubules were perfused at rates ranging from 10 to 100 nl/min with isotonic sodium chloride containing no CO2. Peritubular capillary and intraluminal PCO2 was measured during microperfusion with PCO2 microelectrodes to allow determination of the transepithelial CO2 gradient. The mean PCO2 measured in peritubular capillaries of control rats was 60.6 +/- 1.9 mmHg. Since the perfusion solution initially contained no CO2, a gradient of 60 mmHg was imposed across the tubule epithelium. Intraluminal PCO2 rapidly approached that of the surrounding capillaries. At a tubule perfusion rate of 20 nl/min, the gradient between lumen and blood decreased to 0.9 mmHg, a value not significantly greater than zero. The calculated CO2 permeability coefficient (KCO2) was 3.69 X 10(-5) cm2/s. Addition of either 10(-4) M acetazolamide or benzolamide did not prolong the rapid dissipation of the imposed CO2 gradient. The KCO2 during carbonic anhydrase inhibition was not significantly different from control values. It is concluded that the rat proximal tubule does not present a physiologically significant diffusion barrier to CO2 either in the presence or absence of carbonic anhydrase activity. The previously demonstrated acid disequilibrium pH in the proximal tubule during inhibition of carbonic anhydrase represents an intraluminal accumulation of carbonic acid rather than of carbon dioxide gas.

Postcapillary changes in blood pH in vivo during carbonic anhydrase inhibition

1977 ◽  
Vol 43 (4) ◽  
pp. 582-590 ◽  
Author(s):  
E. D. Crandall ◽  
A. Bidani ◽  
R. E. Forster
Keyword(s):  
Carbonic Anhydrase ◽  
Carbonic Anhydrase Activity ◽  
Stopped Flow ◽  
Arterial Blood ◽  
Blood Ph ◽  
Pulmonary Capillary ◽  
Carbonic Anhydrase Inhibition ◽  
Glass Ph Electrode ◽  
Electrode Chamber

A rapidly responding stopped-flow glass pH electrode apparatus was used to investigate pH changes in blood in vivo after it exits from an exchange capillary. Arterial blood was drawn from anesthetized animals through the apparatus. Temperature and pH of the blood in the electrode chamber were continuously recorded, both during withdrawal and after flow was stopped. Blood pH did not change after stopping flow in control experiments. When benzolamide (2 mg/kg) was given to inhibit carbonic anhydrase activity available to plasma (e.g., due to lysis) while having less effect on intracellular activity, pH increased 0.02–0.04 (t1/2 approximately 8 s) after stopping flow. Administration of acetazolamide (50 mg/kg) resulted in pH decreasing 0.07–0.10 (t1/2 approximately 15 s) after stopping flow. Ventilation for 1 min with N2 resulted in an increased rise in pH for the benzolamide-treated animals but a decreased fall in pH for the acetazolamide-treated animals. These shifts in arterial blood pH after gas exchange are largely due to disequilibrium of [H+] between red cells and plasma at the end of the pulmonary capillary.

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