The Interrelations of Faecal Ammonia, pH and Bicarbonate: Evidence of Colonic Absorption of Ammonia by Non-Ionic Diffusion

1972 ◽  
Vol 43 (1) ◽  
pp. 101-114 ◽  
Author(s):  
P. F. Down ◽  
L. Agostini ◽  
J. Murison ◽  
O. M. Wrong

1. Ammonia, bicarbonate and pH were measured in samples of faecal dialysate from thirteen healthy subjects taking free diets. To observe the effect of marked changes in faecal pH, three subjects were also studied while taking 25 mmol/day of MgCO3 or Na2SO4 by mouth. Both salts increased stool weight without causing diarrhoea, but stool pH was significantly increased by MgCO3 and decreased by Na2SO4. 2. The total ammonia concentration and pH of faecal dialysate were very variable, but showed a highly significant negative correlation similar to that already established in man between urinary excretion of ammonia and urine pH. This relationship was more marked when individual subjects were studied while faecal pH was deliberately varied by administration of MgCO3 and Na2SO4. 3. Faecal bicarbonate concentrations were positively correlated with pH. Faecal Pco2 was usually in the range 40–120 mmHg, the higher Pco2 values being found in the more acid samples. Faecal total ammonia concentrations were negatively correlated with faecal bicarbonate. 4. These findings suggest that passive non-ionic diffusion is the main mechanism by which ammonia is absorbed by the colon, but do not exclude a minor contribution from diffusion of ionized ammonium. Colonic secretion of bicarbonate facilitates non-ionic diffusion of ammonia by providing an anion which is also absorbed by non-ionic diffusion, so maintaining an alkaline intraluminal reaction that continues to generate unionized ammonia.


1979 ◽  
Vol 57 (4) ◽  
pp. 305-312 ◽  
Author(s):  
J. B. McConnell ◽  
J. Murison ◽  
W. K. Stewart

1. The composition of urine-faeces mixture in seven patients with ureterosigmoid anastomosis has been studied by a dialysis in vivo method using cellulose bags. Urine—faeces dialysate obtained from these patients contained much greater amounts of both bicarbonate and total ammonia than has been reported for faecal dialysate in normal subjects. 2. Total ammonia concentrations in urine– faeces specimens obtained by catheter suggest that urine excreted by the kidneys in these patients becomes increasingly acid with increasing systemic acidosis. The highly alkaline nature of urine-faeces mixtures, especially in acidotic patients, indicates rapid alkalinization of the mixture in the colon. It appears that colonic secretion of bicarbonate is a direct consequence of the acidity of urine excreted by the kidney and draining into the colon. 3. The study suggests that the development of hyperchloraemic acidosis in patients with ureterosigmoid anastomosis is due to bicarbonate secretion by the colonic mucosa, with concomitant chloride absorption. With the development of metabolic acidosis, rapid alkalinization of the urine still occurs in the colon, but during further retention of the urine-faeces in the colon some reabsorption of bicarbonate occurs, probably in part by ionic diffusion since chloride concentration in the lumen increases. 4. Evidence suggestive of non-ionic diffusion of ammonia was found in only one patient. It seems probable that higher rates of urea breakdown in other patients mask the expected relationship between total ammonia and bicarbonate.



2020 ◽  
Vol 8 (1) ◽  
pp. 84-101
Author(s):  
Sumoharjo Sumoharjo ◽  
Sulistyawati Sulistyawati

The purpose of this research were to measure the increasing of unionized ammonia during start-up period of biofloc system for growing Nile Tilapia and to figure out its effect on histopathological changes. There was only one treatment that designed with three replication, which was 40 liters of water that contained eight fishes of each weighed 22.. The biofloc system was treated with C/N ration 12:1. Total Ammonia Nitrogen, pH and temperature were measured daily as long as 14 days. the tissue of gill, liver and kidney were cut off at the end of the experiment for histopathological examination. The result of the experiment showed that the peak of unionized ammonia concentration achieved 0.34±0.05 mg/l at 10th day. Then, decreased rapidly to 0.003±0.0009 mg/l at 14th day. The gill, liver, and kidney had regressive changes as physiologic sub lethal response of unionized ammonia expose. Keywords : Biofloc, unionized ammonia, Nile Tilapia, histopatholocal



2013 ◽  
Vol 304 (4) ◽  
pp. F422-F431 ◽  
Author(s):  
Jesse M. Bishop ◽  
Hyun-Wook Lee ◽  
Mary E. Handlogten ◽  
Ki-Hwan Han ◽  
Jill W. Verlander ◽  
...  

The ammonia transporter family member, Rh B Glycoprotein (Rhbg), is an ammonia-specific transporter heavily expressed in the kidney and is necessary for the normal increase in ammonia excretion in response to metabolic acidosis. Hypokalemia is a common clinical condition in which there is increased renal ammonia excretion despite the absence of metabolic acidosis. The purpose of this study was to examine Rhbg's role in this response through the use of mice with intercalated cell-specific Rhbg deletion (IC-Rhbg-KO). Hypokalemia induced by feeding a K+-free diet increased urinary ammonia excretion significantly. In mice with intact Rhbg expression, hypokalemia increased Rhbg protein expression in intercalated cells in the cortical collecting duct (CCD) and in the outer medullary collecting duct (OMCD). Deletion of Rhbg from intercalated cells inhibited hypokalemia-induced changes in urinary total ammonia excretion significantly and completely prevented hypokalemia-induced increases in urinary ammonia concentration, but did not alter urinary pH. We conclude that hypokalemia increases Rhbg expression in intercalated cells in the cortex and outer medulla and that intercalated cell Rhbg expression is necessary for the normal increase in renal ammonia excretion in response to hypokalemia.



Author(s):  
Shiwei Li ◽  
Haoyu Li ◽  
Weiheng Chen ◽  
Jinhui Peng ◽  
Aiyuan Ma ◽  
...  

AbstractIrradiated roast treatment and the ammonia leaching processing were conducted to deal with the low-grade oxide zinc ores. The ZnCO3phase was hard to be attended, which was the reason for the low leaching rate of the complicated zinc ores. The mineral phase transformation of the ZnCO3phase was generated after the ores irradiated in the microwave at the temperature of 673 K. The irradiated ores generated more small particles, it was the reason that the leaching rate of the complicated zinc ores was increased. When the leaching processing of the irradiated roasted ores was conducted under the conditions of the total ammonia concentration of 6 mol/L, the liquid to solid phase ratio of 11:1, the leaching temperature of 298 K, the leaching time of 150 min and the stirring speed of 400 rpm, 88.3 % of zinc could be achieved, which was the maximum leaching rate of the irradiated ores.



2013 ◽  
Vol 9 (2) ◽  
pp. 119-124
Author(s):  
H.S. Spooner ◽  
G.D. Potter ◽  
P.G. Gibbs ◽  
E.M. Eller

Research in other animal models indicate that high protein diets increase urinary calcium (Ca) excretion and may lead to a negative Ca balance and reduced bone density. This study was undertaken to determine the effects of two common levels of dietary protein intake on physiological parameters, Ca absorption, and bone density in immature horses. Sixteen 10-month old horses were blocked by age and sex into two dietary treatments. The control diet (C) was formulated using common ingredients to provide 100% of the National Research Council (NRC) for crude protein (CP), while the high protein diet (H) was formulated at 150% of NRC recommendations. Lower than expected dietary intake resulted in mean protein intake of 769±16 g/d in C and 978±18 g/d in H, equivalent to 91% and 116% of NRC, respectively. Blood, urine, and faeces were collected during the 112-day study to determine pH and mineral balance. Radiographs of the left third metacarpal were used to estimate bone density via radiographic bone aluminum equivalence (RBAE). Although urine pH decreased over time (P<0.001), no change in blood or urine pH was observed due to diet. Faecal pH, normalised to day 0, was significantly lower in H (P<0.02). Faecal Ca loss was greater in H (P<0.005); while Ca absorption and absorption as a percent of intake were lower for H (P<0.02). RBAE of dorsal and palmar cortices increased over time (P<0.001), but no differences were observed between diets. While excess dietary protein decreased faecal pH, increased faecal Ca excretion, and decreased Ca absorption, there appeared to be no effect on bone density over the course of this study.



1991 ◽  
Vol 158 (1) ◽  
pp. 1-18 ◽  
Author(s):  
GEORGE K. IWAMA ◽  
NORBERT HEISLER

Acid-base regulation in rainbow trout acclimated to about 3, 100 and 500 mmol l−1 Na+ and Cl−, at constant water [HCO3−], was assessed during 24h of exposure to 1% CO2 and during recovery. The respiratory acidosis induced by a rise in plasma PCOCO2 to about 1.15kPa (8.5mmHg, 3mmol l−1), 1.33kPa (10mmHg, 100 mmol l−1) or 1.5 kPa (11.2 mmHg, 500 mmol l−1) was partially compensated for by accumulation of plasma HCO3−. The degree of pH compensation depended on the salinity of the environmental water, being about 61, 82 and 88% at 3, 100 and 300 mmol l−1 Na+ and Cl−, respectively. [HCO3−] in animals acclimated to 100 and 500 mmol l−1 rose to higher values than that in fish at 3 mmol l−1. Plasma [Cl−] decreased during hypercapnia as compared to control concentrations in all groups of fish. Plasma [Na+] rose during the first 8 h of hypercapnia in fish acclimated to all three salinities, but recovered towards control values during the remainder of hypercapnia. The rise in plasma [HCO3−] was significantly related to the fall in plasma [Cl−], whereas the changes in plasma [Na+] were unaffected by simultaneous changes in plasma [HCO3−]. Time courses of changes in plasma [Na+] and total ammonia concentration, [Tamm], were similar but in opposite directions. The transepithelial potential (TEP) of blood relative to water was negative, close to zero and positive, averaging −21, −5.8 and +6.2 mV for fish acclimated to 3, 100 and 300 mmol l−1 Na+, respectively. After initiation of hypercapnia, which caused a quite heterogeneous response among groups, a clear trend towards depolarization was observed during the remainder of hypercapnia. These results confirm the role of active HCO3−/Cl− exchange processes for the compensation of extracellular pH during respiratory acidoses in fish.



1996 ◽  
Vol 270 (3) ◽  
pp. F432-F439 ◽  
Author(s):  
S. M. Wall

We have shown that NH4+ and K+ compete for extracellular binding on the Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase) in the rat terminal inner medullary collecting duct (tIMCD). The present study explored whether the Na(+)-K(+)-ATPase modulates transepithelial net acid flux [JH+ = total CO2 absorption (JtCO2) + total ammonia secretion (JtAM)]. Tubules from the tIMCD were dissected from deoxycorticosterone (DOC)-treated rats and perfused in vitro. Perfusate and bath were identical physiological saline solutions containing 25 mM NaHCO3 + 6 mM NH4Cl or were NH4Cl or were NH4Cl free. With NH4+ present, the fall in total CO2 from perfusate to collected fluid (delta tCO2, 2.5 +/- 0.4 mM; n = 6) was accompanied by an increase in collected total ammonia concentration (0.2 +/- 0.1 mM). However, in the absence of NH4Cl, delta tCO2 was only 0.9 +/- 0.2 mM (P < 0.05, n = 5). To determine the mechanism of this NH4Cl-induced increase in net acid secretion, the effect of Na+ pump inhibition on net acid secretion was explored. With NH4Cl present, JCO2 was 3.8 +/- 0.5 pmol.mm-1.min-1 (ouabain absent) but declined to 1.6 +/- 0.3 pmol.mm-1.min-1 with ouabain addition to the bath (n = 7, P < 0.05). Furthermore, in the presence of NH4Cl, intracellular pH (pHi) increased from 7.05 +/- 0.02 to 7.15 +/- 0.02 (P < 0.05, n = 5) with ouabain addition and returned to 7.06 +/- 0.03 (P < 0.05) with ouabain removal. However, in the absence of NH4Cl, ouabain failed to reduce JtCO2 (P = NS, n = 5), and an increase in pHi was not observed (n = 4, P = NS). In conclusion, NH4+ augments net acid secretion likely by serving as a proton source for bicarbonate absorption and titration of other luminal buffers. This ammonium pathway is dependent on the basolateral membrane Na(+)-K(+)-ATPase.



2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Shiwei Li ◽  
Weiheng Chen ◽  
Shaohua Yin ◽  
Aiyuan Ma ◽  
Kun Yang ◽  
...  

AbstractOn the basis of an experiment on ultrasonic enhanced ammonia leaching of low grade zinc oxide ores, the effects of the total ammonia concentration, the ratio between the NH



1985 ◽  
Vol 14 (1) ◽  
pp. 19-35 ◽  
Author(s):  
G. Zeeman ◽  
W.M. Wiegant ◽  
M.E. Koster-Treffers ◽  
G. Lettinga




Sign in / Sign up

Export Citation Format

Share Document