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PubMed2001

Increased blood ammonia in hypoxia during exercise in humans.

The effect of acute hypoxia on blood concentration of ammonia ([NH3]b) and lactate (la-]b) was studied during incremental exercise(IE), and two-step constant workload exercises (CE). Fourteen endurance-trained subjects performed incremental exercise on a cycle ergometer under normoxic (21% O2) and hypoxic (10.4% O2) conditions. Eight endurance-trained subjects performed two-step constant workload exercise at sea level and at a simulated altitude of 5000 m (hypobaric chamber, P(B)=405 Torr; P(O2)=85 Torr) in random order. In normoxia, the first step lasted 25 minutes at an intensity of 85 % of the individual ventilatory anaerobic threshold (AT(vent), ind) at sea level. This reduced workload was followed by a second step of 5 minutes at 115% of their AT(vent), ind. This test was repeated into a hypobaric chamber, at a simulated altitude of 5,000 m. The first step in hypoxia was at an intensity of 65 % of AT(vent), ind., whereas workload for the second step at simulated altitude was the same as that of the first workload in normoxia (85 % of AT(vent), ind). During IE, [NH3]b and [la-]b were significantly higher in hypoxia than in normoxia. Increases in these metabolites were highly correlated in each condition. The onset of [NH3]b and [la-]b accumulation occurred at different exercise intensity in normoxia (181W for lactate and 222W for ammonia) and hypoxia (100W for lactate and 140W for ammonia). In both conditions, during CE, [NH3]b showed a significant increase during each of the two steps, whereas [la-]b increased to a steady-state in the initial step, followed by a sharp increase above 4 mM x L(-1) during the second. Although exercise intensity was much lower in hypoxia than in normoxia, [NH3]b was always higher at simulated altitude. Thus, for the same workload, [NH3]b in hypoxia was significantly higher (p<0.05) than in normoxia. Our data suggest that there is a close relationship between [NH3]b and [la-]b in normoxia and hypoxia during graded intensity exercises. The accumulation of ammonia in blood is independent of that of lactate during constant intense exercise. Hypoxia increases the concentration of ammonia in blood during exercise.

Adult↗
PubMed2003

Improved method for determination of ammonia and nitrite oxidation activities in mixed bacterial cultures.

A simple and reliable method to measure the activity of ammonia and nitrite oxidisers in mixed bacterial cultures was developed. The developed method differentiates between the ammonia and nitrite oxidisers by consecutive injection of NO2- and NH4+. The main advantage of this method is that it avoids the use of metabolic inhibitors for ammonia or nitrite oxidisers, as used by other methods. Moreover, it allows measuring of the short-term effect of an inhibitor on both the ammonia and nitrite oxidisers in one test under controlled environmental conditions (pH, temperature). The developed method was applied to determine the inhibitory effects of salt (NaCl up to 15 g Cl/l) on an enriched culture of nitrifying bacteria. The results of the method demonstrate its potential to accurately determine the individual activities of nitrite and ammonia oxidisers.

Ammonia↗
PubMed1998

Effect of ammonia on the anaerobic degradation of protein by a mesophilic and thermophilic biowaste population.

The influence of ammonia on the anaerobic degradation of peptone by mesophilic and thermophilic populations of biowaste was investigated. For peptone concentrations from 5 g l-1 to 20 g l-1 the mesophilic population revealed a higher rate of deamination than the thermophilic population, e.g. 552 mg l-1 day-1 compared to 320 mg l-1 day-1 at 10 g l-1 peptone. The final degree of deamination of the thermophilic population was, however, higher: 102 compared to 87 mg NH3/g peptone in the mesophilic cultures. If 0.5-6.5 g l-1 ammonia was added to the mesophilic biowaste cultures, deamination of peptone, degradation of its chemical oxygen demand (COD) and formation of biogas were increasingly inhibited, but no hydrogen was formed. The thermophilic biowaste cultures were most active if around 1 g ammonia l-1 was present. Deamination, COD degradation and biogas production decreased at lower and higher ammonia concentrations and hydrogen was formed in addition to methane. Studies of the inhibition by ammonia of peptone deamination, COD degradation and methane formation revealed a Ki (50%) for NH3 of 92, 95 and 88 mg l-1 at 37 degrees C and 251, 274 and 297 mg l-1 at 55 degrees C respectively. This indicated that the thermophilic flora tolerated significantly more NH3 than the mesophilic flora. In the mesophilic reactor effluent 4.6 x 10(8) peptone-degrading colony-forming units (cfu)/ml were culturable, whereas in the thermophilic reactor effluent growth of only 5.6 x 10(7) cfu/ml was observed.

Amines↗
PubMed2003

Nitrogen-13 ammonia cardiac positron emission tomography in mice: effects of clonidine-induced changes in cardiac work on myocardial perfusion.

We explored the feasibility of imaging myocardial perfusion and of demonstrating the flow changes in response to reduction of cardiac work non-invasively in anesthetized mice using high spatial resolution, dedicated small-animal positron emission tomography (microPET). In 31 C57BL/6 mice anesthetized with pentobarbital or isoflurane, (13)N-ammonia was injected intravenously and images were recorded with microPET from 4 to 20 min. Fifteen mice (group 1) were studied consecutively at baseline (BL) and after reduction of heart rate (HR) with intraperitoneal injection of clonidine (CLN) to investigate effects of CLN-induced reduction of cardiac work on myocardial (13)N-ammonia uptake. Eight mice (group 2) were imaged repeatedly at BL and eight mice (group 3) twice after CLN to examine reproducibility. Total myocardial (13)N-ammonia accumulation was determined from the transaxial images and normalized for injected dose (%ID). HR was 412+/-97 beats/min at BL and 212+/-44 beats/min after CLN (P<0.0001). In group 1, the %ID significantly decreased from 1.50%+/-0.27% at BL to 1.29%+/-0.28% after CLN (P<0.0001). In groups 2 and 3, reproducibility of %ID was good (y=0.96x+0.105, SEE=0.212%, r(2)=0.749, P<0.0001). In conclusion, (13)N-ammonia microPET imaging demonstrated non-invasively a reduction of myocardial perfusion induced by clonidine in mice. We believe this study is of importance as the first report on myocardial perfusion imaging and flow validation in in vivo mouse hearts with a left ventricular size of only 5 mm using (13)N-ammonia and PET. MicroPET will aid in elucidating cardiac pathophysiology in transgenic mice and monitoring effects of gene therapies on myocardial perfusion.

Ammonia↗
PubMed2003

Excretory nitrogen metabolism in the Chinese fire-belly newt Cynops orientalis in water, on land, or in high concentrations of environmental ammonia.

The Chinese fire-belly newt Cynops orientalis reverts to an aquatic mode of living when sexually mature. Despite living in water, sexually mature C. orientalis maintained high capacity for hepatic urea synthesis. However, it had a lower rate of urea production than other terrestrial amphibians because endogenous ammonia could diffuse out to the external medium as NH3. This conserves cellular energy because urea synthesis is energetically expensive. Simultaneously, C. orientalis also reduced the rate of urea excretion, and excreted 33% of the total nitrogenous waste as ammonia. Upon exposure to land, C. orientalis increased the rate of urea synthesis from accumulating endogenous ammonia. The increased rate of urea synthesis was within the inherent capacity of the hepatic ornithine-urea cycle; there was no induction of hepatic carbamoyl phosphate synthetase or ornithine transcarbamoylase activities and there was no reduction in ammonia production. When exposed to water containing 75 mmol.l(-1) NH4Cl, the rates of both urea synthesis and urea excretion increased. Under such experimental conditions, the ornithine-urea cycle may be operating close to its limit; glutamine began to accumulate in the body, and endogenous ammonia production via amino acid catabolism was reduced.

Ammonia↗
PubMedDate not supplied

Age does not affect airway pH and ammonia as determined by exhaled breath measurements.

Measurement of airway pH has been used as a diagnostic and monitoring tool in a variety of pulmonary diseases in adults. These diseases occur across a wide age range. Few investigations have addressed the effects of aging on airway pH and ammonia. The aim of this study was to determine whether exhaled breath condensate (EBC) measurements of pH and ammonia differ in older and younger populations of normal subjects. Twenty-three normal younger individuals (median age-24 years) and 25 normal older participants (median age-72 years) were investigated by measuring EBC for pH and ammonia using recommended methodologies. EBC ammonia and pH values were not significantly different between younger and older individuals. Thus, we conclude that EBC ammonia and pH do not appear to be affected by age.

Adolescent↗
PubMed2001

Influence of ambient temperature on plasma ammonia and lactate accumulation during prolonged submaximal and self-paced running.

This study examined the effects of heat stress on the accumulation of plasma ammonia, lactate, and urate during prolonged running. Nine highly trained endurance runners completed two running trials in a counterbalanced fashion in cool (15 degrees C) and in hot (35 degrees C) humid (60% relative humidity) conditions. Subjects ran on a motorised treadmill at 70% of peak treadmill running speed for 30 min (submaximal) followed by a self-paced 8-km performance run. Blood was drawn at pre-exercise, end-submaximal and end-performance run and analysed for plasma ammonia, lactate, and urate. Four subjects failed to complete the performance run in the heat and the performance times for the rest of the subjects was increased from 27.3 (0.6) min in cool conditions to 31.3 (1.2) min in hot conditions (P < 0.05). The end-performance rectal temperature was 38.6 (0.1) and 39.2 (0.1) degrees C (P<0.05) in cool and hot conditions, respectively. Differences in plasma lactate at the end of submaximal running were not significant. However, at the end of performance runs lactate was 6.0 (0.9) m mol x l(-1) in cool and 3.1 (0.5) mmol x l(-1) in hot conditions, values that were significantly different (P<0.05). Plasma ammonia increased from pre-exercise to approximately equal to 59 micromol x l(-1) at the end-submaximal runs for both coditions and further at the end of performance runs to 108.5 (11) micromol x l(-1) (P<0.05) in hot but not in cool conditions. Plasma urate increased from pre-exercise to 311.2 (25.9) micromol x l(-1) at end-submaximal runs and to approximately equal to 320.4 micromol x l(-1) at end-performance runs in hot and cool environments. The findings that plasma urate accumulation was similar at the completion of running in both conditions, while ammonia was significantly augmented in hot conditions compared with cool, suggest that ammonia accumulation during heat stress exercise might be derived from sources other than purine catabolism.

Adult↗
PubMed2002

Intracellular pH regulation in guinea-pig caecal and colonic enterocytes during and after loading with short-chain fatty acids and ammonia.

Absorption of short-chain fatty acids (SCFA) and ammonia implies considerable fluxes of protons across the epithelium of the large intestine. Efficient regulation of intracellular pH (pH(i)) is therefore essential in these cells. The aim of the present study was to examine the effects of SCFA and of ammonia on pH(i), on pH(i) regulation and to characterize the mechanisms involved in pH(i) regulation in surface enterocytes of the guinea-pig caecal and colonic mucosa. Intact epithelia from the caecum and the distal colon were mounted in a microperfusion chamber. pH(i) was measured by fluorescence microscopy using 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). Addition of SCFA or ammonia to the serosal side changed the enterocyte pH(i) markedly, whereby ammonia caused larger changes in pH(i) than SCFA. In contrast, addition of SCFA to the mucosal solution had no effect on pH(i) and ammonia increased pH(i) only slightly. Basolaterally located pH(i) regulation mechanisms, Na(+)-H(+) exchange and Cl(-)-HCO(3)(-) exchange, are involved mainly in returning pH(i) to normal values. It is concluded that, due to apparently lower permeability of the apical membranes, the caecal and colonic epithelium is protected against pH(i) disturbances caused by the naturally high luminal SCFA and NH(3) concentrations. The major regulation mechanisms of pH(i) are located in the basolateral membrane of the enterocytes.

Acid-Base Equilibrium↗
PubMed2004

Impacts of reduced sulfur components on active and resting ammonia oxidizers.

While there has been significant research on the nature and extent of the impact of inhibitory reduced sulfur with respect to anaerobic (e.g., methanogenic and sulfidogenic) microbial systems, only limited study has yet been conducted on the comparable effects of soluble sulfides which might occur within aerobic wastewater treatment systems. Admittedly, aerobic reactors would not normally be considered conducive to the presence of reduced sulfur constituents, but there do appear to be a number of processing scenarios under which related impacts could develop, particularly for sensitive reactions like nitrification. Indeed, the following scenarios might well involve elevated levels of reduced sulfur within an aerobic reactor environment: (1) mixed liquor recycle back through sulfide-generating anaerobic zones (e.g., in conjunction with biological nutrient removal processes, etc.), (2) high-level side-stream sulfide recycle via sludge digestion, etc., back to aerobic reactors, and (3) high-level influent sulfide inputs to wastewater treatment facilities via specific industrial, septage, etc., streams. The objective of this study was, therefore, to determine the subsequent metabolic impact of soluble sulfide under aerated and unaerated conditions, focusing in particular on ammonia-oxidizing bacteria due to their critical first-step role with nitrification. The obtained results indicated that, under catabolically active conditions, cultures of ammonia oxidizers were extremely sensitive to the presence of sulfide. At total soluble sulfide concentrations of 0.25 mg l(-1) S, active ammonia oxidation was completely inhibited. However, immediately following the removal of this soluble sulfide presence, ammonia oxidation started to recover; and it continued to improve over the next 24 h. Similar sulfide impact tests conducted with inactive ammonia oxidizers exposed during anaerobic conditions, albeit at higher dosage levels, also revealed that their subsequent aerobic activity would correspondingly be retarded. These results indicated that, after sulfide exposure under unaerated conditions, subsequent aerobic oxidative activity rates rapidly decreased as the soluble sulfide exposure was increased from 0.5 gm l(-1) S to 5 mg l(-1) S and that further reductions in this activity progressively developed as the concentration was increased to 200 mg l(-1) S. The recovery following unaerated exposure to sulfide was significantly higher at pH 7, as compared with pH 8, and although the specific nature of this variation was not established, a hypothetical explanation appeared warranted.

Aerobiosis↗
PubMed1993

Nitrogen-13 ammonia perfusion imaging: relation to metabolic imaging.

PET provides an advanced imaging technology that permits the accurate definition of regional tracer distribution. In combination with N-13 ammonia, PET allows for the sensitive and specific detection of coronary artery disease. Results of several studies indicate the superiority of this approach compared with standard thallium-201 tomographic imaging. In addition, regional blood flow can be accurately measured with N-13 ammonia PET, and this approach can be used in conjunction with pharmacologic stress imaging to quantify regional flow reserve. In combination with metabolic markers, N-13 ammonia is capable of assessing myocardial viability. Furthermore, the N-13 ammonia PET approach may differentiate among various forms of cardiomyopathy. More studies are needed to define the cost-benefit ratio of the N-13 ammonia PET technique for the management of patients with coronary artery disease or cardiomyopathy.

Ammonia↗
PubMed1986

The effect of sodium benzoate on ammonia toxicity in rats.

At 9.5 mmoles/kg body weight, sodium benzoate sharply increased mortality in rats subsequently challenged with ammonia. Fasted animals were less sensitive to potentiation of ammonia toxicity by benzoate than were fed animals. At 2.5 mmoles/kg body weight, benzoate was observed to protect fasted animals against ammonia toxicity. Measurements of ammonia disappearance, urea formation, and hippurate synthesis in suspensions of isolated hepatocytes indicate that benzoate potentiates ammonia toxicity by inhibiting the urea cycle.

Acetates↗
PubMed1982

Ammonia and methionine sulfoximine intoxication.

Intoxication with ammonium acetate abolished the suppression of action potential generation by cortical postsynaptic inhibition, i.e. produced 'disinhibition', due to the inactivation of neuronal Cl- extrusion. With the occurrence of disinhibition cerebral ammonia increased to 445% of normal; glutamine increased to 170%. Methionine sulfoximine (MSO), an inhibitor of glutamine synthetase, produced disinhibition about 3 h after administration; at this time cerebral ammonia was increased to 290% of normal, glutamine was unchanged. Intoxication with MSO for less than 3 h significantly decreased the amount of ammonium acetate needed to produce disinhibition at cerebral ammonia concentrations ot 340-430% of normal. MSO produces an endogenous ammonia intoxication which: (i) decreases the amount of exogenous ammonia required to affect cortical postsynaptic inhibitions; and (ii) eventually becomes sufficiently severe to disturb cortical inhibitory neuronal interactions by itself.

Acetates↗
PubMed1975

The fluorimetric determination of ammonia in protein-free filtrates of human blood plasma.

Ammonia has been determined in filtrates of human plasma after precipitation of the proteins by perchloric acid. After restoration of the pH to around 7.5, addition of 2-oxoglutarate, NADH and glutamate dehydrogenase (GDH) convers the ammonia to L-glutamate with oxidation of the NADH to NAD. This latter reaction was utilised in two ways. In the first, reduction of native NADH fluorescence under the conditions of the GDH reaction provided a measure of ammonia concentration. In the second, residual NADH was destroyed by acid treatment, and the fluorescent product generated from NAD under strongly alkaline conditions was assayed. The optimal requirements for both methods were defined, their linearity and precision ascertained, and their relative merits compared. The first method was convenient for "one-off" estimations, and the second for larger batches. Ammonia concentration increased in plasma and in acid protein-free filtrates of plasma irrespective of the conditions of storage; however when the latter were neutralised, storage at -20 degrees C was effective. The distribution of plasma ammonia concentration in healthy subjects was log-normal. The range for males was 21-58 mumol/1 and for females 17-51 mumol/1; this difference was statistically significant (P less than 0.01).

Ammonia↗
PubMed1993

Gastric ammonia has a potent ulcerogenic action on the rat stomach.

BACKGROUND: The pathophysiological mechanism by which Helicobacter pylori induces mucosal injury has not been clarified. The aim of this study was to investigate the role of urea, urease, and ammonia in rat gastric mucosal lesions using an ex vivo chamber model. METHODS: Two groups of rats, normotensive rats and those subjected to ischemia, were studied. The gastric mucosa was examined histologically and macroscopically, and the transmucosal potential difference was measured. RESULTS: Instillation of urea into the stomach generated ammonia in the presence of urease. The amount of ammonia was increased depending on the concentration of urea and was closely associated with the severity of the histological lesions. The exposure of the stomach to 15-60 mmol/L ammonium hydroxide induced both a reduction in transmucosal potential difference and microscopic damage to the gastric mucosa in normotensive rats. Moreover, 15-60 mmol/L ammonium hydroxide produced severe macroscopic gastric lesions in the rats subjected to ischemia. CONCLUSIONS: These results show that ammonia is deleterious to the gastric mucosa and suggest the importance of urea, urease, and ammonia in the pathophysiology of gastric diseases in H. pylori-infected patients.

Action Potentials↗
PubMed1994

Isotopic analyses of nitrogenous compounds from the Murchison meteorite: ammonia, amines, amino acids, and polar hydrocarbons.

The combined volatile bases (ammonia, aliphatic amines, and possibly other bases), ammonia, amino acids, and polar hydrocarbons were prepared from the Murchison meteorite for isotopic analyses. The volatile bases were obtained by cryogenic transfer after acid-hydrolysis of a hot-water extract and analyzed by combined gas chromatography-mass spectrometry of pentafluoropropionyl derivatives. The aliphatic amines present in this preparation comprise a mixture that includes both primary and secondary isomers through C5 at a total concentration of > or = 100 nmoles g-1. As commonly observed for meteoritic organic compounds, almost all isomers through C5 are present, and the concentrations within homologous series decrease with increasing chain length. Ammonia was chromatographically separated from the other volatile bases and found at a concentration of 1.1-1.3 micromoles g-1 meteorite. The ammonia analyzed includes contributions from ammonium salts and the hydrolysis of extractable organic compounds, e.g., carboxamides. Stable isotope analyses showed the volatile bases to be substantially enriched in the heavier isotopes, relative to comparable terrestrial compounds delta D < or = +1221%; delta 13C = +22%; delta 15N = +93%). Ammonia, per se, was found to have a somewhat lower delta 15N value (+69%) than the total volatile bases; consequently, a higher delta 15N (>93%) can be inferred for the other bases, which include the amines. Solvent-extractable polar hydrocarbons obtained separately were found to be enriched in 15N (delta 15N = +104%). Total amino acids, prepared from a hydrolyzed hot-water extract by cation exchange chromatography, gave a delta 15N of +94%, a value in good agreement with that obtained previously. Nitrogen isotopic data are also given for amino acid fractions separated chromatographically. The delta 15N values of the Murchison soluble organic compounds analyzed to date fall within a rather narrow range (delta 15N = +94 +/- 8%), an observation consistent with their formation, or formation of their precursors, by interstellar chemistry.

Amines↗
PubMed1989

Ammonia and urea dynamics in the Lake Magadi tilapia, a ureotelic teleost fish adapted to an extremely alkaline environment.

The tilapia Oreochromis alcalicus grahami, which thrives under harshly alkaline conditions in Lake Magadi, Kenya, was studied in its natural environment (pH = 10, total CO2 = 180 mmol/L, osmolality = 525 mOsm/kg, 30-36.5 degrees C). At rest, this species excretes all nitrogenous waste as urea. This is the first known instance of complete ureotelism in an entirely aquatic teleost fish. Very small 'apparent' ammonia excretion (less than 5% of overall N excretion) was attributable to faecal/bacterial production. Ammonia excretion could not be induced by feeding, reduced temperature, or exposure to pH 7. Exhaustive exercise induced only a small efflux of ammonia. Urea output was inhibited completely by pH 7 water and partly by exhaustive exercise, and greatly stimulated by exposure to 500 mumol/L NH3 (at pH 10). A related species, nominally Oreochromis nilotica, which lives in freshwater at circumneutral pH in the same geographic region, excretes 85% ammonia-N and 15% urea-N at pH 7 in the standard teleost fashion. Urea-N efflux increased to 33% upon transfer of O. nilotica to pH 10 in freshwater. Urea output in this species was only marginally stimulated by exposure to 500 mumol/L NH3 (at pH 7). Plasma and white muscle urea levels were 4- to 5-fold higher in O. a. grahami than in O. nilotica, and plasma levels increased between caudal and cardiac sampling sites, indicating hepatic ureagenesis. Blood pH and PNH3 levels, when corrected for sampling artifact, were unusually high in O. a. grahami. We hypothesize that complete ureotelism in O. a. grahami is an evolutionary response to the problems of excreting ammonia into highly buffered water at pH 10 and/or acid-base balance in this extreme environment.

Acid-Base Equilibrium↗
PubMed1992

Influence of lactate, ammonia, and osmotic stress on adherent and suspension BHK cells.

Adherent and suspension Baby Hamster Kidney (BHK) 21c13 cells were cultivated in a 2.5-1 stirred-tank reactor with indirect aeration. Cell concentration and viability as well as glucose, lactate, ammonia, and protein concentrations in the medium and intracellular and extracellular activities of the intracellular enzymes were determined off-line. The concentrations of glucose, lactate, ammonia, and the activity of lactate dehydrogenase in the culture medium were monitored on-line. The cell/cell fragment size distribution was determined by laser flow cytometer off-line. In several runs, the size distributions were ascertained on-line by a laser flow cytometer. The influence of lactate, ammonia, and osmotic pressure on the viability and biological parameters of the suspension cells was evaluated. In Roux flasks, lactate and ammonia had considerable influence on the cell properties; in stirred tank reactors, these influences were negligible up to 9.5 g l-1 lactate and 150 mg l-1 NH+4 ion concentrations. The influence of high osmolarity on the biological parameters of the cells was much less in the stirred-tank than in the Roux flasks. The adhesion of adherent cells on a surface was impeded neither by the lactate (up to 6 g l-1) nor by the ammonia concentration (up to 150 mg l-1). However, with increasing osmolarity, the fraction of the cells adhered to a surface reduced to below 5% (at 680 mOsmol l-1).

Ammonia↗
PubMed1994

Histopathology of kidney of Channa punctatus exposed to chronic nonlethal level of Elsan, mercury, and ammonia.

Histopathological changes in the head and trunk kidneys of Channa punctatus induced by chronic nonlethal levels of Elsan (211 ppb), mercuric chloride (16.7 ppb), and aqueous ammonia (15.64 ppm) were studied on 7, 28, 63, and 90 days of exposure. The pathology of the head kidney was characterized by degeneration and dispersion of interrenal and chromaffin tissue and necrosis in the haemopoietic elements. Kidney lesions were observed throughout the entire experimental period in fish exposed to Elsan and mercuric chloride. In contrast, the lesion induced by exposure to aqueous ammonia began to heal during the first phase of treatment. Marked abnormalities in trunk kidney histology were also found. Renal lesions consisted of minimal to mild multifocal, acute tubular epithelial degeneration, karyolysis, and dilation or shrinkage of Bowman's capsule and glomerulus. Elsan treatment resulted in a highly significant decrease in the dimension of Bowman's capsule and glomerulus at all days of sampling, except on Day 28. The response of the fish trunk kidney tissue to mercuric chloride was similar to that observed with Elsan exposure in terms of the alteration in the mean dimensions of Bowman's capsule and glomerulus. The response to ammonia was significant reduction in the size of Bowman's capsule and glomerulus throughout the experimental period except at Day 28. Little dilation of Bowman's capsule and a significant dilation of glomerulus were found at Day 28 of ammonia exposure. This study demonstrated that a chronic nonlethal exposure to Elsan, mercuric chloride affect both endocrine and excretory parts of the kidney while ammonia specifically damages the excretory part of the kidney of C. punctatus.

Ammonia↗