Solubility of ammonia in human plasma

Jacquez, John A.; Poppell, J. William; Jeltsch, Rudolph

doi:10.1152/jappl.1959.14.2.255

Cited by 40 publications

(17 citation statements)

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“…Although the rate of ammonium production cannot be determined from the data presented in this work, an estimate of differences in the production of ammonia by renal cortical tissue in the two groups of animals can be obtained by calculating the pNH3 of the cortex. If it is true that ammonia entry into the tubule lumen is due to nonionic diffusion of the free base NH3 where protonation and entrapment occurs (30), and that NH3 is in equilibration throughout all structures located in the cortex (31,32), then given the in situ pH and ammonium concentration of fluid obtained near the end of the proximal tubule, the pNH3 of the renal cortex can be calculated with the following formula (33,34) (35) and the solubility coefficient (a) of 0.626 (34), cortical pNH3 averaged 1,267±234 mmHg X 10-6 in the RK group, twofold the value in the sham-operated group (658±70 mmHg X 10-6). If intracellular pH fell during acidosis (36) and if ammonia entry was due solely to diffusion and no increase in synthesis occurred, then one would expect that the cortical pNH3 of the RK group would be lower than that of the sham-operated group.…”

Section: Discussionmentioning

confidence: 99%

Effect of Reduced Renal Mass on Ammonium Handling and Net Acid Formation by the Superficial and Juxtamedullary Nephron of the Rat

Buerkert¹,

Martin²,

Trigg³

et al. 1983

J. Clin. Invest.

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A B S T R A C T Papillary and surface micropuncture were used to study the handling of ammonium and the formation of net acid by surface nephrons, deep nephrons, and the terminal segment of collecting duct (CD) after renal mass was reduced by two-thirds. Net acid excretion by the remnant kidney (RK) was significantly reduced, averaging 794±81 neq/min (SE) compared with 1,220±105 neq/min after sham operation (P < 0.001), due to a decrease in ammonium excretion (494±54 vs. 871±79 nmol/min in controls, P < 0.001). Urinary pH and titratable acid excretion were not different in the two groups of animals. After RK formation, ammonium delivery to the end of the proximal tubule increased nearly threefold and averaged 66.2±5.6 compared with 18.4±2.9 pmol/min in controls, (P < 0.001). This greater delivery of ammonium was primarily due to renal tubule entry rather than to changes in the filtered load and was only partially related to the differences in flow rate. Ammonium processing by deep nephrons was profoundly affected by a reduction in renal mass. Although absolute delivery of ammonium was greater to the bend of Henle's loop (BHL), the difference could be accounted for on the basis of an increase in nephron size. Received for publication I November 1982 and in revised form 23 February 1983. with the RK. Hydrogen secretion in the proximal segments of deep and surface nephrons did not increase in proportion to the decrease in renal mass and as a consequence bicarbonate delivery to the end of the proximal tubule of surface nephrons and to the BHL of deep nephrons was increased.When renal mass was reduced FDNH. to the base of the terminal CD doubled but did not change by the tip. In both groups FDNI4+ to the base of the CD was greater than to the end of the distal tubule. However, the increase was the same. On the other hand, the increase in the net acid index between the end of the distal tubule and the base of the CD was profoundly greater in rats with an RK. This difference was primarily due to bicarbonate reabsorption rather than enhanced ammonium reentry. Indeed, >400% of the fractional ammonium delivered to the end of the proximal tubule was lost from the tubule fluid. The data suggest that the decrease in acid excretion by the RK is due to two factors. First, hydrogen secretion in the proximal segments of both nephron populations fails to increase in the proportion to the reduction in renal mass. Second, a reduced reentrapment of ammonia, rather than its impaired production, causes ammonium excretion to decrease.

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Section: Discussionmentioning

confidence: 99%

Effect of Reduced Renal Mass on Ammonium Handling and Net Acid Formation by the Superficial and Juxtamedullary Nephron of the Rat

Buerkert¹,

Martin²,

Trigg³

et al. 1983

J. Clin. Invest.

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“…It yields OH-rather than H+ ions as follows: NH3 +H20 = NH4OH NH4+ +OH-. 801 C. CLAIRE AICKIN AND R. C. THOMAS This reaction has a pKa' of 9-02 in human plasma at 370 C (Jacquez, Poppell & Jeltsch, 1959). At pH 7 40 we were therefore only able to apply ammonia at low concentrations (0.48 mm with 20 m-equiv NH+).…”

Section: Claire Aickin and R C Thomasmentioning

confidence: 99%

Micro‐electrode measurement of the intracellular pH and buffering power of mouse soleus muscle fibres.

1977

The Journal of Physiology

177

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SUMMARY1. The intracellular pH (pHi) of surface fibres of the mouse soleus muscle has been measured in vitro using recessed-tip pH-sensitive microelectrodes.2. In 5 % CO2 and pH 7 40, the mean pH1 was 7 07 + 0 007 (s.E. of mean) at 370 C and 7-23 + 0.01 at 280 C. The difference between these two values is the same as the change in neutral pH between 37 and 280 C.3. Alteration of the CO2 level at constant external pH caused a biphasic change in pH1 with a rapid displacement followed by a slower partial recovery. Because the recovery was incomplete, different stable pHi values were recorded at different CO2 levels, the higher the CO2 the lower the pHi. The differences in pHi were highly significant both at 37 and 280 C.4. Alteration of the CO2 level at constant external pH also changed the membrane potential (Em), an increase in CO2 leading to an increased Em. The dependence of Em on the CO2 level was much smaller in the fasttwitch muscle, extensor digitorum longus, than in soleus.5. Changing external pH, either by alteration of the bicarbonate or CO2level of the Ringer solution, caused pHi to change by a mean 38-7 % of the external pH change. The change in pHi was accomplished about 10 times more rapidly, and in the same direction, by altering CO2 than by altering the bicarbonate. 6. Application of external NH3 and NH+ caused a rapid intracellular alkalinization followed by a slower acidification. On removal of external NH3 and NH+, there was a large and rapid acidification, followed by a fairly rapid recovery in pHi.7. The size of the pH1 changes occurring on alteration of the CO2 level at both constant external pH and constant external bicarbonate, and on removal of external NH3 and NH+, suggests a non-CO2 buffering

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“…Body temperature may fall below normal in an anesthetized animal or the animal may be febrile for some other cause. Some variation of a NH3 and of pK'a with temperature has been shown to exist (17).…”

Section: Pk'a Determinationsmentioning

confidence: 99%

The Existence of Ammonia in Blood in Vivo With Observations on the Significance of the Nh4+–nh3 System *

Bromberg

Robin²,

Forkner³

1960

J. Clin. Invest.

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The development of refined methods for determination of blood ammonia in the past 50 years has resulted in a gradual lowering of the reported concentrations in the peripheral venous blood of normal man (1). After extensive work with a microdiffusion technique, Conway and Cooke concluded that the normal in vivo peripheral venous level of the blood ammonia nitrogen in man was operationally zero, but that rapid liberation of ammonia from certain precursors occurred after shedding to produce in vitro values of about 35 Amoles ammonia-nitrogen (NH3-N) per L blood (2). Identical conclusions were reached by Koprowski and Uninski in their work on dog blood (3), using Conway's method. The results of more recent investigations using different techniques (4-7) have indicated that peripheral venous blood does contain significant amounts of ammonia in vivo. This conflict has not been resolved despite frequent use of the Conway method in many investigations of human ammonia metabolism in the past decade.The present experiments were stimulated by the observation that dogs receiving intravenous infusions of ammonium salts excreted measurable amounts of NH8 gas in expired air (8). This ammonia was presumably derived from the dissolved NH. gas which must exist in equilibrium

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Solubility of ammonia in human plasma

Cited by 40 publications

References 0 publications

Effect of Reduced Renal Mass on Ammonium Handling and Net Acid Formation by the Superficial and Juxtamedullary Nephron of the Rat

Effect of Reduced Renal Mass on Ammonium Handling and Net Acid Formation by the Superficial and Juxtamedullary Nephron of the Rat

Micro‐electrode measurement of the intracellular pH and buffering power of mouse soleus muscle fibres.

The Existence of Ammonia in Blood in Vivo With Observations on the Significance of the Nh4+–nh3 System *

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