Renal Excretion of Bicarbonate and Hydrogen Ions: Effects of Mannitol Diuresis in Normal Man

1972 ◽  
Vol 43 (4) ◽  
pp. 561-567 ◽  
Author(s):  
P. A. Poole-Wilson ◽  
J. Patrick ◽  
G. A. MacGregor ◽  
N. F. Jones
Keyword(s):  
Renal Excretion ◽  
Hydrogen Ion ◽  
Normal Adult ◽  
Hydrogen Ions ◽  
Acid Excretion ◽  
Urinary Ph ◽  
Titratable Acid ◽  
Initial Ph ◽  
Normal Man ◽  
Urinary Acid

1. The pattern of urinary acid excretion during mannitol diuresis was studied in five normal adult subjects. 2. At peak diuresis (osmolal clearance 19·3–27·9 ml/min), the urinary pH approached 6·9 irrespective of the initial pH. 3. Total hydrogen ion excretion fell sharply during mannitol diuresis. Changes in the excretion of ammonium and titratable acid were small and variable, but in each subject bicarbonate excretion increased markedly. 4. Despite previous conflicting published results urinary acid excretion during mannitol diuresis in man resembles that in the dog and is dominated by a bicarbonate diuresis.

Impaired renal H+ secretion and NH3 production in mineralocorticoid-deficient glucocorticoid-replete dogs

1977 ◽  
Vol 232 (2) ◽  
pp. F136-F146 ◽  
Author(s):  
H. N. Hulter ◽  
L. P. Ilnicki ◽  
J. A. Harbottle ◽  
A. Sebastian
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Ammonium Excretion ◽  
Acid Excretion ◽  
Concentration Gradients ◽  
Urine Ph ◽  
Hydrogen Ion Concentration ◽  
Titratable Acid ◽  
Potassium Restriction ◽  
Potassium Retention

When the administration of exogenous mineralocorticoid hormones was discontinued in adrenalectomized dogs maintained on glucocorticoid, net acid excretion decreased due largely to a reduction in urinary ammonium excretion (UNH4+V), and hyperchloremic hyperkalemic metabolic acidosis occurred and persisted. The reduction in UNH4+V was not associated with an increase in urine pH (UpH) or a decrease in urine flow, but correlated with the severity of hyperkalemia and was mitigated by dietary potassium restriction. UpH decreased to values as low as 5.3. During acidosis, UpH varied directly with UNH4+V, but in relation to UNH4+V, UpH exceeded that in acid-fed mineralocorticoid-replete dogs. Extrapolated to UNH4+V=0, however, UpH was not significantly different in the two groups (5.27 vs. 5.44). When distal delivery of sodium was increased by infusion of sodium phosphate, titratable acid excretion increased in both groups but pateaued at lower rates in the mineralocorticoid-deficient dogs. These results suggest that in mineralocorticoid-deficient dogs, renal ammonia production is diminished, in part due to potassium retention and hyperkalemia; renal hydrogen ion secretory capacity is reduced even when sodium and buffer delivery to the distal nephron is not reduced; and the ability of the kidney to generate normally steep urine-to-blood hydrogen ion concentration gradients is unimpaired.

Dissociation of CO2 hydration and renal acid secretion in the dogfish, Squalus acanthias

1986 ◽  
Vol 250 (2) ◽  
pp. F288-F293 ◽  
Author(s):  
E. R. Swenson ◽  
T. H. Maren
Keyword(s):  
Carbonic Anhydrase ◽  
Acid Secretion ◽  
Hydrogen Ion ◽  
Phenol Red ◽  
Urine Ph ◽  
Urinary Ph ◽  
Bicarbonate Reabsorption ◽  
Acid Urine ◽  
Titratable Acid

Maximal rates of renal hydrogen ion secretion and bicarbonate reabsorption in the dogfish were stimulated by intravascular infusion of acidic and basic buffers: bicarbonate, phosphate, phenol red, dimethadione (DMO), imidazole, and piperazine-N,N'-bis(2 ethanesulfonic acid) (PIPES). There was no difference in titratable acid secretion or urinary pH after bicarbonate infusion despite a sevenfold increase in plasma bicarbonate. Bicarbonate reabsorption was increased 12-fold and showed no evidence of reaching a maximum. This was not altered by methazolamide, as expected, since there is no renal carbonic anhydrase in seagoing fish. Imidazole resulted in the greatest augmentation of renal titratable acid secretion (33----390 mueq . h-1 . kg-1) and did not alter urinary pH. Inhibition of organic base secretion by Darstine had no effect on the imidazole-induced maximal rate of acid secretion. This rate was compared with that of hydrogen ion generation calculated from the uncatalyzed reactions of CO2 and H2O or OH-, maximizing PCO2 and OH- gradients and reaction volumes in vivo. These calculated chemical rates could only account for 9-14% of the measured maximal acidification rate. Thus the powerful process that maintains constant acid urine pH is not only independent of carbonic anhydrase but can function well in a low CO2 environment in which the reactions CO2 + H2O or CO2 + OH- do not furnish enough protons for H+ secretion or HCO3- reabsorption. We conclude that following the cellular protolysis of water, processes other than those involving CO2 buffering of OH- permit H+ to engage in the formation of urine.

Renal Handling of Calcium, Magnesium, Inorganic Phosphate and Hydrogen Ions during Prolonged Exposure to Elevated Carbon Dioxide Concentrations

1973 ◽  
Vol 45 (6) ◽  
pp. 751-764 ◽  
Author(s):  
S. P. Gray ◽  
J. E. W. Morris ◽  
C. J. Brooks
Keyword(s):  
Urinary Excretion ◽  
Inorganic Phosphate ◽  
Prolonged Exposure ◽  
Serum Levels ◽  
Hydrogen Ions ◽  
Acid Excretion ◽  
Renal Handling ◽  
Carbon Dioxide Concentrations ◽  
Calcium Magnesium ◽  
Urinary Acid

1. Fifteen healthy young men were exposed to an atmosphere of 0–7% CO2 in air for 7 weeks. 2. For 1 week before and during the exposure to CO2, serum calcium, magnesium and inorganic phosphate (Pi) levels were measured at intervals, together with 24 h urinary excretion of these three components, and net urinary acid excretion. 3. The urinary excretion of Ca2+, Mg2+ and Pi fell during exposure to CO2, whereas the serum levels of these components increased. 4. Serum levels of calcium were inversely correlated with urinary Ca2+ excretion both in control conditions and during exposure to CO2 5. An increase in urinary acid excretion in the third to fourth week of exposure to CO2 was associated with an increase in the urinary excretion of Ca2+, but not of Mg2+. 6. It is suggested that there is a difference from the normal in the renal handling of H+ and Ca2+ ions during exposure to CO2 which may lead to a retention of Ca2+ in the tissues.

Factors affecting renal handling of sodium, hydrogen ions, and bicarbonate by the fetus

1986 ◽  
Vol 251 (2) ◽  
pp. F226-F231
Author(s):  
G. J. Kesby ◽  
E. R. Lumbers
Keyword(s):  
Renal Excretion ◽  
Hydrogen Ions ◽  
Ammonium Ions ◽  
Renal Handling ◽  
Fetal Sheep ◽  
Factors Affecting ◽  
Titratable Acid ◽  
Sodium Hydrogen ◽  
Arterial Ph ◽  
Age Dependent

Renal excretion of acid and reabsorption of bicarbonate was studied in 17 chronically catheterized fetal sheep aged 121-143 days. The rates of excretion of titratable acid (0.16-6.2 mumol/min) and ammonium (1.2-9.7 mumol/min) were variable. Urinary phosphate excretion was significantly greater (P less than 0.001) than the excretion of titratable acid. Of the filtered bicarbonate load 80-100% was reabsorbed. In 9 of the 17 fetuses net acid excretion was positive. Bicarbonate, sodium, and chloride reabsorption were related to glomerular filtration rate (GFR) (P less than 0.0005). The increase of GFR results in an increase in the excretion of titratable acid (P less than 0.001), phosphate (P less than 0.0005), and ammonium (P less than 0.001). These relationships could account for the age-dependent increase in renal excretion of acid (P less than 0.0005), ammonium (P less than 0.025), and bicarbonate reabsorption (P less than 0.0005). Arterial pH affected the rates of excretion of titratable acid (P less than 0.005), ammonium ions (P less than 0.05), and net acid (P less than 0.025). It is concluded that the fetal kidneys can excrete protons and generate bicarbonate. This ability increases with age due mainly to the concomitant increase in GFR.

Hydrogen Ion Beam Processing of Single Crystal Diamond Chips

1994 ◽  
Vol 354 ◽  
Author(s):  
Shuji Kiyohara ◽  
Iwao Miyamoto
Keyword(s):  
Surface Roughness ◽  
Single Crystal ◽  
Incidence Angle ◽  
Ion Beam ◽  
Etching Rate ◽  
Hydrogen Ion ◽  
Hydrogen Ions ◽  
Ion Beam Etching ◽  
Single Crystal Diamond ◽  
Before And After

AbstractIn order to apply ion beam etching with hydrogen ions to the ultra-precision processing of diamond tools, hydrogen ion beam etching characteristics of single crystal diamond chips with (100) face were investigated. The etching rate of diamond for 500 eV and 1000 eV hydrogen ions increases with the increase of the ion incidence angle, and eventually reaches a maximum at the ion incidence angle of approximately 50°, then may decrease with the increase of the ion incidence angle. The dependence of the etching rate on the ion incidence angle of hydrogen ions is fairly similar to that obtained with argon ions. Furthermore, the surface roughness of diamond chips before and after hydrogen ion beam etching was evaluated using an atomic force microscope. Consequently, the surface roughness after hydrogen ion beam etching decreases with the increase of the ion incidence angle within range of the ion incidence angle of 60°.

scholarly journals 48 Urinary Acid Excretion in the Intact Lamb Fetus

1967 ◽  
Vol 1 (3) ◽  
pp. 212-212
Author(s):  
Fred G Smith ◽  
Richard Bashore
Keyword(s):  
Acid Excretion ◽  
Urinary Acid

The response of the kidney of the freshwater rainbow trout to true metabolic acidosis

1980 ◽  
Vol 84 (1) ◽  
pp. 227-244 ◽  
Author(s):  
K. A. Kobayashi ◽  
C. M. Wood
Keyword(s):  
Lactic Acid ◽  
Metabolic Acidosis ◽  
Blood Lactate ◽  
Renal Excretion ◽  
Total Acid ◽  
Time Courses ◽  
Lactate Levels ◽  
Urinary Acid ◽  
Proton Load ◽  
Lactate Excretion

Infusion of lactic acid into the bloodstream of trout produced a short-lived depression of blood pH and a long-lasting elevation of blood lactate. The lactate injected was distributed in a volume of 198 ml/kg. Renal excretion of lactate anion and total acid increased by approximately equal amounts during the period of high blood lactate levels, but total renal loss over 72 h accounted for only 2% of the lactate load and 6% of the proton load. Comparable differences in the time courses of blood lactate and pH changes occurred when lactacidosis was induced endogenously by normocapnic hypoxia. The immediate response of the kidney was similar to that with lactic acid infusion, but there was a long-lasting (12–72 + h) elevation of urinary acid efflux that was not associated with lactate excretion. Following hypoxia, renal excretion over 72 h accounted for 1% of the estimated lactate load and 12–25% of the proton load. A renal lactate threshold of 4–10 muequiv/ml prevents significant urinary lactate excretion. The response of the trout kidney to true metabolic acidosis is similar to that of the mammalian kidney.

Impact of hydrogen ion on fasting ketogenesis: feedback regulation of acid production

1982 ◽  
Vol 242 (3) ◽  
pp. F238-F245 ◽  
Author(s):  
V. L. Hood ◽  
E. Danforth ◽  
E. S. Horton ◽  
R. L. Tannen
Keyword(s):  
Acid Production ◽  
Metabolic Regulation ◽  
Feedback Regulation ◽  
Hydrogen Ion ◽  
Acid Excretion ◽  
Acid Base Balance ◽  
Acid Base ◽  
Urine Ph ◽  
Ion Production ◽  
Base Balance

To determine whether acid-base balance regulates hydrogen ion production, seven obese volunteers were given NaHCO3 and NH4Cl (2 mmol.kg-1.day-1) during two separate 7-day fasts. On days 5-7 plasma bicarbonate was lower in the NH4Cl fasts (14.0 +/- 1.4 mM) than in the NaHCO3 fasts (18.3 +/- 1.1 mM), while urine pH and net acid excretion did not differ. Acid production (acid excretion minus intake) was greater by 204 mmol/day in the NaHCO3 fasts (274 +/- 16 mmol/day) than in the NH4Cl fasts (70 +/- 19 mmol/day). Ketoacid excretion, which reflected net ketoacid production, paralleled acid production, decreasing from 213 +/- 24 mmol/day in the NaHCO3 fasts to 67 +/- 18 mmol/day in the NH4Cl fasts. Thus, during starvation, alterations in hydrogen ion intake and the associated changes in acid-base balance modify the net production of endogenous acid by influencing the synthesis or utilization of ketoacids. Although the specific site of this metabolic regulation is undefined, these results indicate that systemic acid-base status can exert feedback control over hydrogen ion production.

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