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PubMed1997

Calcium excretion, apparent calcium absorption and calcium balance in young and elderly subjects: influence of protein intake.

The present study was conducted to investigate the effect of dietary protein on urinary Ca excretion, apparent Ca absorption and Ca balance in young and elderly subjects. Young adults (n 29) and elderly persons (n 26) consumed diets containing 12% (diet A) and 21% (diet B) of total energy as protein for 3 weeks according to a randomized crossover design. Results showed no differences between the two age groups with respect to the interaction between protein intake and Ca excretion (both in urine and in faeces), apparent Ca absorption and Ca balance. Therefore analyses were done for both age groups separately and also for the whole group. In elderly persons and in the whole group the Ca excretion in faeces (as a percentage of Ca intake) was lower during the higher protein intake (elderly: diet A, 106 (SEM 7)%; diet B, 86 (SEM 7)%; P = 0.018; whole group: diet A, 99 (SEM 4)%; diet B, 84 (SEM 4)%; P = 0.003). In young adults faecal Ca excretion tended to be lower when they consumed diet B (diet A: 94 (SEM 5)%; diet B: 83 (SEM 6)%; P = 0.093). Relative urinary Ca excretion was greater during the higher protein intake in young adults and in the whole group while relative urinary Ca excretion was not different in the elderly (diet A: 15 (SEM 1)%, 14 (SEM 1)%, 15 (SEM 1)%; diet B: 16 (SEM 1)%, 16 (SEM 1)%, 17 (SEM 2)% for the whole group, the young and elderly subjects respectively, P = 0.019; P = 0.016; P = 0.243). The resulting Ca balance was not influenced by the amount of protein in the diet in young adults. Values for the elderly and for the whole group showed that the Ca balance during diet A was significantly more negative compared with Ca balance during diet B, despite the higher urinary Ca excretion during diet B. It can be concluded that increasing the protein intake from 12 to 21% of total energy intake had no negative effect on Ca balance.

Adult↗

PubMed1998

Urinary excretion of purine derivatives as an index of microbial-nitrogen intake in growing rabbits.

Three experiments were carried out to establish a response model between intake and urinary excretion of purine compounds. In Expt 1 the relationship between the intake of purine bases (PB) and the excretion of total purine derivatives (PD) was determined in seven growing rabbits with a mean initial live weight (LW) of 2.03 (SE 0.185) kg, aged 70 d, each fitted with a wooden neck collar to prevent caecotrophagy. They were fed on five experimental diets formulated with different levels of nucleic acids (0.00, 3.75, 7.50, 11.25, 15.00 g yeast-RNA/kg diet). The relationship between intake of purine (x, mumol/kg W0.75) and total urinary PD excretion (y, mumol/kg W0.75), y= 0.56 + 0.67x (r2 O.86; RSD 0.338), indicated that about 70% of duodenal PB were recovered as urinary PD and that the endogenous contribution was constant and independent of dietary PB supply. Endogenous excretion of PD (allantoin and uric acid) was measured in a second experiment using six rabbits fed on a purine-free diet and fitted with neck collars to avoid caecotrophagy. Basal daily urinary excretion values for allantoin and uric acid were 532 (SE 33.9) and 55 (SE 7.3) mumol/kg W0.75 respectively; xanthine and hypoxanthine were not found in urine samples and therefore the sum of allantoin and uric acid should comprise the total excretion of PD (588 (SE 40.1) mumol/kg W0.75). The xanthine oxidase (EC 1.2.3.2) activity in plasma, liver, duodenum, jejunum and kidney was measured in a third experiment. The activities of xanthine oxidase in duodenal and jejunal mucosa, liver and kidney were: 0.61 (SE 0.095), 0.37 (SE 0.045), 0.035 (SE 0.001) and 0 units/g fresh tissue respectively and in plasma 2.96 (SE 0.094) units/1. The results show that urinary excretion of PD may be a useful tool to estimate duodenal PB input and microbial protein intake once the relationship between PB and N has been established in caecal micro-organisms.

Allantoin↗

PubMed2004

Urinary excretion of purine derivatives as an index of microbial protein synthesis in the camel (Camelus dromedarius).

Five experiments were carried out to extend knowledge of purine metabolism in the camel (Camelus dromedarius) and to establish a model to enable microbial protein outflow from the forestomachs to be estimated from the urinary excretion of purine derivatives (PD; i.e. xanthine, hypoxanthine, uric acid, allantoin). In experiment 1, four camels were fasted for five consecutive days to enable endogenous PD excretion in urine to be determined. Total PD excretion decreased during the fasting period to 267 (SE 41.5) micromol/kg body weight (W)0.75 per d. Allantoin and xanthine + hypoxanthine were consistently 86 and 6.1 % of total urinary PD during this period but uric acid increased from 3.6 % to 7.4 %. Xanthine oxidase activity in tissues (experiment 2) was (micromol/min per g fresh tissue) 0.038 in liver and 0.005 in gut mucosa but was not detected in plasma. In experiment 3, the duodenal supply of yeast containing exogenous purines produced a linear increase in urinary PD excretion rate with the slope indicating that 0.63 was excreted in urine. After taking account of endogenous PD excretion, the relationship can be used to predict purine outflow from the rumen. From the latter prediction, and also the purine:protein ratio in bacteria determined in experiment 5, we predicted the net microbial outflow from the rumen. In experiment 4, with increasing food intake, the rate of PD excretion in the urine increased linearly by about 11.1 mmol PD/kg digestible organic matter intake (DOMI), equivalent to 95 g microbial protein/kg DOMI.

Allantoin↗

PubMed2001

Correlations between biochemical markers of bone resorption and creatinine excretion.

There were two reasons for doing this study. The first was to assess whether expressing biochemical markers of bone resorption as a ratio to creatinine excretion influences the correlations between them. The second was to assess whether biochemical markers of bone resorption are correlated with creatinine excretion, which is a biomarker of muscle mass. Three biochemical markers of bone resorption, free deoxypyridinoline (DPD), N-telopeptides (NTx) and C-telopeptides (CTx), together with creatinine (cr), were measured in 24-h urine samples of 45 healthy people (26 women and 19 men). The urinary concentrations of DPD, NTx and CTx were highly correlated with each other. These relationships were weakened, or no longer statistically significant, when the markers were expressed as a ratio to cr excretion. The 24-h excretion of each of the markers was correlated with 24-h cr excretion in men, but only 24-h DPD was correlated with 24-h cr excretion in the women. The men had significantly higher 24-h excretion rates of each of the markers than the women did. Since muscle mass is related to skeletal mass, these data suggest that in healthy people the rate of bone resorption may be a function of skeletal size as well as the rate of bone turnover. For small human studies 24-h urine sampling is recommended in preference to untimed sampling. However, for clinical purposes, or for large clinical trials, this may not be practical.

Adult↗

PubMed2002

Application of (1)H- and (19)F-NMR spectroscopy in the investigation of the urinary and biliary excretion of 3,5-, 2,4-ditrifluoromethylbenzoic and pentafluorobenzoic acids in rat.

1. The metabolism and excretion of 2,4-, 3,5-ditrifluoromethyl- and pentafluorobenzoic acids were studied in the bile-cannulated rat using (1)H- and (19)F-NMR spectroscopy following intraperitoneal administration at 50 mg kg(-1). 2. Pentafluorobenzoic acid was excreted in the urine entirely unchanged. No detectable compound or metabolites were eliminated in the bile. A total of 63.5 +/- 6.7% of the dose was recovered in the 24-h collection period. 3. In the case of 2,4-ditrifluromethyl benzoic acid, 83.9 +/- 5.2% of the dose was recovered in the 24h after administration, with about 52% being excreted in the urine and 32% in the bile. The majority of the material present in the urine was unchanged parent compound. In bile, some 60% of the compound-related material excreted was present as transacylated ester glucuronide conjugates. 4. For 3,5-ditrifluoromethylbenzoic acid, 49.6 +/- 5.3% of the dose was recovered in the 24-h collection period, with about 22% being excreted in the urine and 28% in the bile. The material excreted in both the urine and bile was a mixture of the parent acid and transacylated ester glucuronides. 5. Urinary excretion in bile-cannulated animals was similar to that found in studies using non-cannulated animals dosed at 100mg kg(-1).

Animals↗

PubMed1997

Ingestion of chromium(VI) in drinking water by human volunteers: absorption, distribution, and excretion of single and repeated doses.

This study examines the magnitude of hexavalent chromium [Cr(VI)] absorption, distribution, and excretion following oral exposure to 5 and 10 mg Cr(VI)/L in drinking water administered as a single bolus dose (0.5 L swallowed in 2 min) or for 3 d at a dosage of 1 L/d (3 doses of 0.33 L each day, at 6-h intervals). Adult male volunteers ingested deionized water containing various concentrations of potassium chromate, and samples of urine, plasma, and red blood cells (RBCs) were collected and analyzed for total chromium throughout the studies. In the bolus dose studies, a fairly consistent pattern of urinary chromium excretion was observed, with an average half life of about 39 h. However, 4-d total urinary chromium excretion and peak concentrations in urine and blood varied considerably among the 5 volunteers. Studies of repeated exposure to smaller volumes ingested at a more gradual rate (i.e., 0.33 L over 5-15 min) showed similar urinary chromium excretion patterns but generally lower chromium uptake/excretion. Given that sustained elevations in RBC chromium levels provide a specific indication of chromium absorption in the hexavalent state, these data suggest that virtually all (> 99.7%) of the ingested Cr(VI) at 5 and 10 mg Cr(VI)/L was reduced to Cr(III) before entering the blood-stream. The interindividual differences in total chromium uptake and excretion are plausibly explained by ingestion of appreciable doses on an empty stomach, which likely results in the formation of well-absorbed Cr(III) organic complexes in gastrointestinal tissues and possibly the blood. The lack of any clinical indications of toxicity in the volunteers and the patterns of blood uptake and urinary excretion of chromium are consistent with a predominant uptake of Cr(III) organic complexes [derived from Cr(VI)] that are excreted more slowly than inorganic forms of Cr(III). Therefore, it appears that the endogenous reducing agents within the upper gastrointestinal tract and the blood provide sufficient reducing potential to prevent any substantial systemic uptake of Cr(VI) following drinking-water exposures at 5-10 mg Cr(VI)/L. Based on these data, the chemical environment in the gastrointestinal tract and the blood is effective even under relative fasting conditions in reducing Cr(VI) to one or more forms of Cr(III).

Absorption↗

PubMed1998

Increased urinary polyamine excretion in unselected cancer patients related to host factors.

Unselected patients with solid malignant tumours were investigated in order to determine whether they displayed elevated urinary excretion of polyamines; and if so, whether polyamine excretion in such patients predicts disease progression, or is secondary to host and systemic factors. Thirty-eight male and female patients with generalized solid, mainly gastrointestinal, malignant tumours were investigated. Ten male patients operated on for infrarenal aortic aneurysms and 15 otherwise healthy male and female patients hospitalized for minor surgical procedures served as reference patients, representing individuals with and without metabolic stress. Urine samples were collected from all patients during 24 h for measurement of both total and individual excretion of polyamines during three consecutive days. Polyamine excretion was not significantly increased in cancer patients when compared by analysis of variance among the three patient groups. However, polyamine excretion was significantly elevated in both cancer and stressed, non-cancer patients compared with patients without stress (p < 0.05). A multivariate analysis indicated that plasma protein and albumin concentrations, abnormal liver function tests and liver metastasis predicted variation in polyamine excretion in cancer patients (p < 0.01), but this was unrelated to survival. Our results demonstrate that increased polyamine excretion in cancer patients is related more to host factors than to tumour growth itself.

Aged↗

PubMed1996

Calculogenic potential of galactose and fructose in relation to urinary excretion of lithogenic substances in vitamin B6 deficient and control rats.

OBJECTIVE: Calculogenic potential of refined sugars galactose and fructose was examined in vitamin B6 deficient and control rats in terms of their capacity to increase urinary excretion of lithogens. METHODS: Male albino rats were fed vitamin B6 deficient diet with 51.7% sucrose+ starch or galactose or fructose as the source of carbohydrate. Pair-fed controls were maintained for all the groups for a period of four weeks. Twenty-four hour urine samples obtained at weekly intervals were analyzed for creatinine, calcium, oxalate, phosphate and uric acid. Microscopic urinalysis was performed at the end of the study. RESULTS: Urinary calcium excretion increased with respect to baseline in all groups except vitamin B6 control group. On day 28, galactose and fructose-fed rats demonstrated significant hypercalciuria as compared to the sucrose + starch fed group. Vitamin B6 deficient rats (irrespective of the sugar fed) excreted significantly greater urinary calcium compared to pair-fed controls. Oxalate excretion was significantly increased in rats fed galactose compared to those fed fructose or sucrose + starch. Vitamin B6 deficiency further increased oxalate excretion by 1.5, 1.9 and 1.7 fold in sucrose + starch, fructose or galactose fed animals, respectively. Urinary uric acid excretion was enhanced only in fructose-fed rats. There was no change in urinary excretion of creatinine and phosphate in different experimental and control groups. Increased urinary saturation with lithogens caused pronounced crystalluria in all the vitamin B6 deficient groups as well as galactose control group. CONCLUSION: The results suggest galactose ingestion is associated with a greater propensity to form calcium oxalate kidney stones than fructose. Calculogenic potential of galactose and fructose is further enhanced in vitamin B6 deficiency.

Animals↗

PubMed2002

A glucomannan and chitosan fiber supplement decreases plasma cholesterol and increases cholesterol excretion in overweight normocholesterolemic humans.

OBJECTIVE: Both chitosan and glucomannan have demonstrated hypocholesterolemic effects. A recent study in rats indicates that the combination of the two is also a potent hypocholesterolemic agent that increases fecal fat excretion. The objective of the present study was to determine the hypocholesterolemic effect of a supplement containing equal amounts of chitosan and glucomannan on blood lipid concentrations and fecal excretion of fat, neutral sterols and bile acids. METHODS: Twenty-one overweight normocholesterolemic subjects (11 males and 10 females) were fed 2.4 g/day of a supplement containing equal amounts of chitosan and glucomannan. Prior to taking the supplement (initial period) and after 28 days (final period), blood was drawn for measurement of serum lipids and a three-day fecal sample collected for determination of fat, neutral sterol and bile acid excretion. Subjects maintained their normal dietary and activity patterns during the study. RESULTS: Caloric intake and intake of fat and dietary fiber (excluding the supplement) did not differ between the initial and final periods. Serum total, HDL and LDL cholesterol concentrations were significantly lower (p < 0.05) in the final period compared to the initial period. Serum triacylglycerol concentration did not change between periods. There was a trend towards greater fecal excretion of neutral sterols and bile acids (p = 0.13 and 0.16, respectively) in the final period. However, fecal fat excretion did not differ between periods. CONCLUSIONS: Serum cholesterol reduction by a chitosan/glucomannan supplement is likely mediated by increased fecal steroid excretion and is not linked to fat excretion.

Adolescent↗

PubMedDate not supplied

Comparison of the urinary excretion time courses of pyrene-1,6-dione, pyrene-1,8-dione and 1-hydroxypyrene in rats intravenously exposed to pyrene.

The urinary excretion time courses of pyrene-1,6-dione (P16D), pyrene-1,8-dione (P18D) and 1-hydroxypyrene (1-OHP) were compared in Sprague-Dawley and Wistar rats. Groups of five male rats, of about 200 g of body weight, were injected intravenously with 0.05, 0.5, 5 and 50 micromol pyrene kg-1 of body weight. Urine was collected at 2, 4, 6, 8, 10, 12, 18, 24, 30, 42 and 48 h post-dosing. Pyrene metabolites were measured by high-performance liquid chromatography (HPLC)/fluorescence after enzymatic hydrolysis of the glucurono- and sulfo-conjugates, extraction on Sep-Pak C18 cartridges and, for the analysis of dione metabolites, derivatization to stable diacetoxypyrene molecules. Over the 48-h sampling period, on average 17.4-25.6% of the injected pyrene was excreted overall as P16D, 6.4-8.8% as P18D and 0.6-0.8% as 1-OHP in the urine of Sprague-Dawley rats. By comparison, on average 10.3-14.7% of the intravenous pyrene dose was recovered as P16D, 4.8-6.4% as P18D and 0.3-0.4% as 1-OHP in the urine of Wistar rats. In both strains of rats there was no clear effect of the dose on the 0-48-h cumulative urinary excretion of P18D and 1-OHP over the entire dose range, while the percentage of dose recovered overall as P16D in urine at the highest dose (50 micromol kg-1) was statistically lower than at the other doses. The 0-48-h cumulative percentage of pyrene dose excreted as metabolites in the urine of Sprague-Dawley rats was also significantly higher than in Wistar rats (p<0.01) exposed under identical conditions. As for the urinary excretion-time courses of the different metabolites, for a given dose and strain of rats, excretion curves of P16D, P18D and 1-OHP generally evolved in parallel. There was also no clear effect of the dose on the excretion rate, thus half-life, of pyrene metabolites, except for P16D in Sprague-Dawley rats at the highest dose where elimination tended to be slower compared with the other doses (p<0.01). The average first-order elimination half-life of P16D, P18D and 1-OHP was 4.0, 5.7 and 4.1 h, respectively, in Sprague-Dawley rats, and 5.1, 6.1 and 5.1 h, respectively, in Wistar rats (all doses combined but excluding the highest dose for P16D). This study showed the relative importance of metabolic pathways leading to diones compared with 1-OHP. These dioxygenated metabolites appear to be interesting biomarkers of pyrene exposure at environmentally and occupationally relevant doses. Their adequacy as biomarkers of human exposure has yet to be confirmed.

Animals↗

PubMed2002

Urinary excretion kinetics of 1-hydroxypyrene in rats subchronically exposed to pyrene or polycyclic aromatic hydrocarbon mixtures.

The urinary excretion kinetics of 1-hydroxypyrene (1-OHP) were studied in male Sprague-Dawley rats exposed orally, on Tuesdays and Fridays for 10 consecutive weeks, to 0.046 mg/kg/d of pyrene or 0.3, 1 or 3 mg/kg/d of polycyclic aromatic hydrocarbon (PAH) mixtures containing pyrene (0.046, 0.15, and 0.46 mg/kg/d, respectively). During the subchronic exposure, 24-h urine samples were collected on Mondays (prior to exposure) and Tuesdays (after exposure) for all exposure groups. During a 14-d period following last exposure in rats treated with 3 mg/kg/d of PAH mixture, 24-h urine samples were collected at frequent time intervals (0-24, 48-72, 96-120, 144-168, 193-217, 313-338 h). Whatever the administered dose, repeated exposures to pyrene and PAH mixtures resulted in a progressive time-dependent increase in the daily urinary excretion of 1-OHP. After 10 wk of treatment, daily excretion rates were on average 5 times higher than those observed after the first administration. Following the subchronic exposure to 3 mg/kg/d of PAH mixture, the time profile of 1-OHP excretion in rat urine showed a multiphasic elimination. An average first-order apparent elimination half-life of 26.5 h could be estimated for the 48-168 h period following the end of the exposure. The observed time-dependent increase in 1-OHP excretion values upon repeated exposures to PAHs does not appear to result from a PAH enzyme induction effect of pyrene metabolism to 1-OHP. Rather, the slow release of residual pyrene accumulated in a long-term compartment and/or the enterohepatic recirculation of 1-OHP and other pyrene metabolites may play significant roles in the observed urinary excretion kinetics of 1-OHP. Furthermore, the absence of mixture effect on the urinary excretion of 1-OHP suggests that 1-OHP is a good bioindicator of exposure to complex PAH mixtures, in the dose range used in this study.

Animals↗

PubMed1981

Cadmium, copper, and zinc excretion and their binding to metallothionein in urine of cadmium exposed rats.

The urinary excretion of Cd, Cu, and Zn was measured in rats injected with 0.5 mg/kg Cd, sc, 6 d/wk for u to 25 wk. Gel chromatographic analysis for these urinary metals were also carried out. The Cd excretion slightly increased at first, followed by a rapid increase with concurrent appearance of proteinuria around 6 wk. During these early weeks, excretion of Cu in the urine showed a more pronounced increase and reached a plateau level (three to four times the control value). Zn excretion showed a sharp increase accompanied by proteinuria, following a slight increase, and reached about 10 times the control value. A linear relation was obtained between Cd and both Cu and Zn in the urine before proteinuria appeared. Metallothionein (MT) in the urine was associated only with Cu before the appearance of proteinuria. Cu-MT increased with increasing excretion of urinary Cu. Cd-containing MT first appeared in the urine after on onset of proteinuria, but it was still rich in Cu at first. Fron 10 wk, urinary MT showed an excess increase and contained much Cd than Cu. Zn-MT was not observed in the urine. Most of the urinary Zn was recovered from the lower-molecular-weight fractions. The results suggest that MT is directly involved in urinary excretion of Cu in the absence of renal damage and in the excretion of Cd as well as Cu after the appearance of toxicity in Cd-exposed rats.

Animals↗

PubMed1986

Sex and age differences in mercury distribution and excretion in methylmercury-administered mice.

Sex differences in mercury distribution and excretion after single administration of methylmercury chloride (MMC, 5 mg/kg) were studied in mice. A sex difference in urinary mercury excretion was found in sexually mature mice (age of 7 wk) of C57BL/6N and BALB/cA strains. Males showed higher mercury levels in urine than females, though no significant difference was found in fecal mercury levels 24 h post exposure to MMC. The higher urinary excretion rates in males accounted for significant lowering of mercury levels in the brain, liver, and blood, but not in the kidney, which showed higher values. At 5 min, however, these sex difference was found only in the kidney, showing higher levels in males. Changes in mercury distribution with time were studied in C57BL/6N mice. The brain mercury increased in both sexes up to 3 d, and decreased only in males on d 5. Liver and blood mercury decreased with time in both sexes, and these were constantly higher in females than in males. Renal mercury in males decreased to similar levels to females on d 3. The sex differences at various ages were studied with C57BL/6N mice 24 h after dosing. Two-week-old mice, the youngest in this study, did not show significant sex difference in the mercury distribution and excretion, and their urinary mercury levels were much lower as compared to the older mice. Then, urinary mercury excretion in both sexes increased at 4 wk of age and then decreased at 45 wk of age. At 4, 7, 10, and 45 wk of age, males showed higher urinary mercury levels than females. These studies demonstrated sex and age differences in the mercury distribution and urinary excretion after methylmercury administration in mice. From these findings, it has been suggested that urinary mercury excretion may be related to sex hormones, especially androgens.

Aging↗

PubMed1975

[Excretion of zinc in lactating cows receiving various supply of zinc].

Studies were carried out with 5 lactating cows receiving a semisynthetic diet to trace the pattern of zinc excretion in the faeces, urine and milk under conditions of Zn depletion and repletion. Faecal Zn concentrations were found to be drastically reduced during a 6-week period of Zn depletion. The Zn supply to the animals at different levels of Zn repletion (varying between 22 mg and 436 mg Zn per kg) was well reflected in the corresponding faecal Zn concentrations. Similarly, faecal Zn excretion expressed as the percentage of Zn supplied with the diet was shown to change with the level of Zn supply. In the range between 6 mg and 54 m Zn per kg of dietary dry matter the level of relative faecal Zn excretion increased from 42% to 56% whereas with higher Zn supplements (up to 436 mg/kg) only slight increases (up to 60%) were observed. This indicates that the organism exhibits a strong tendency to maintain a physiological balance; this tendency is all the more pronounced with increasing Zn depletion; thus after 19 weeks of Zn depletion as little as 25% of the administered amount of Zn was excreted in the faeces. The average minimum of urinary Zn concentrations was 0.25 mg Zn per litre. The Zn concentrations in urine were not found to be dependent on the Zn supply. The level of relative Zn excretion in the milk was markedly increased despite the reduced concentrations of milk Zn during the periods of Zn deficiency. At the beginning of Zn depletion rather more zinc was released with the milk than was taken up with the Zn deficient diet. The mean proportion of milk Zn in the total amount of dietary Zn over the 6-week depletion period was 91%. With Zn amounts of 22 mg, 54 mg, 87 mg, 108 mg, 130 mg and 436 mg per kg of diet 23.7%, 13.1%, 12.9%, 5.7%, 4.3%, and 1.7% of the dietary Zn were excreted with the milk. Thus, a relative decrease of Zn excretion in the milk was observed, i.e. relative to the level of Zn supplementation.

Animal Feed↗

PubMed1983

[Factors altering allantoin excretion by sheep and goats].

We have studied the factors of variation of the urinary allantoin excretion with sheep billy goats and goats during digestibility trials. The urinary excretion of nitrogen allantoin (Nal) is highly correlated with the intake of digestible organic matter (DOM) and soluble nitrogen (Ns) for the sheeps billy goats and goats. By multiple regression we have estimated the daily endogenous excretion of Nal at 160 mg (goats) and 60 mg (sheeps and billy goats) respectively 8.5 and 2.6 mg/kg W0.75. The differences observed between sheeps and billy goats (Nal = 27.3 +/- 11.3 and 32.2 +/- 9.4 mg/kg W0.75) agree with the differences observed in the DOM and Ns intakes. The dairy goats eat more than the billy goats (69.5 against 52.0 DOM/kg W0.75 and 412 against 315 mg Ns/kg W0.75) but they excrete less Nal (36.3 mg against 42.3/kg W0.75). During the first two weeks of lactation the goats with negative N balance excrete more Nal than the goats with positive N balance (78 mg Nal against 57 mg/100 g DOM). Although large variations of DOM and Ns, the amount of Nal excreted before and after kidding doesn't vary. In these last conditions the general relation between Nal and intake of DOM and Ns no longer holds. Since the disponible energy (MOD) and soluble nitrogen intake supplies for the rumen microorganisms influence the amount of synthetised microbials protein (and so the amount of nucleic acids entering the duodenum) our regressions confirm the assumption that the excretion of Nal is related with the nucleic acids metabolism. However when Nal is utilised as an index of the nucleic acids catabolism, the factors that are able to create the variations either in the endogenous production of allantoin (uterine involution, bodily mobilisation, foetus growth, mammary gland development) or in the nucleic acids valorization must be taken into account.

Allantoin↗

PubMed1984

[Effect of glutamic acid content of the diet on the catabolic rate of isotope-labeled glutamic acid in rats. 3. Determination of 14CO2 and 15N excretion following intragastric infusion of 14C- and 15N-glutamic acid].

Male rats (body weight 100 g) received during a 8 days experimental feeding period diets with different contents in glutamic acid. The daily feed intake was restricted to the energy maintenance level of 460 kJ/kg0.75. The diet contained a mixture of L-amino acids corresponding to the pattern of egg protein except glutamic acid. Glutamic acid was added successively at 10 levels (0 to 14,8% of dry matter) and the resulting diets were fed to groups of 4 animals each. At the end of the experimental feeding period 14C- and 15N-labelled glutamic acid were applied by intragastric infusion. CO2- and 14CO2-excretion was measured during the following 4 hours and the urinary N- and 15N-excretion during the following 24 hours. The CO2-excretion decreased from 53 to 44 mmol CO2/100 g body weight with increasing levels of dietary glutamic acid. This change seems to result from the increasing proportion of amino acids as an energetic fuel. While the amount of oxidized glutamic acid increased with increasing supplements of glutamic acid the relative 14CO2-excretion decreased from 57 to 48% of the applied radioactivity. The urinary 15N-excretion during 24 hours was 31% of the given amount of 15N if no glutamic acid was included in the diet. This proportion increased successively up to 52% in the case of the highest supply of glutamic acid. Because the total N-excretion increased at the same extent as the 15N-excretion a complete mixing of the NH2-groups resulting from glutamic acid due to desamination with the ammonia pool was assumed. No correlation between glutamic acid content of the diet and specific radioactivity of CO2 or atom-% 15N excess of urinary N was observed.

Animal Feed↗

PubMed1986

[Allantoin excretion of wethers in variations of raw protein and energy administration].

216 values of urinary allantoin excretion were received from 8 digestibility trials, which included 48 rations with different protein and energy content. Thus relations between allantoin excretion and food intake and ration composition, respectively, could be evaluated. Additionally variations in N balance were measured, since there is a close relation to allantoin metabolism. Fecal N excretion was elevated with increasing energy intake, but varied only slightly with modified N supply. Urinary N excretion and also N retention increased with higher N intake. On the other hand urinary N losses were reduced with increasing energy supply and part of the saved nitrogen was deposed into the body. There was a distinct increase in allantoin excretion with raised protein intake, when N supply ranged generally low. But with a daily supply of crude protein above 60 to 70 g there was no significant further response in allantoin excretion. Allantoin excretion increased linearly with higher energy supply. Several restrictions for conclusions on the extent of microbial protein production in the digestive tract estimated out of measured allantoin values were discussed.

Allantoin↗

PubMed2002

Increased urinary excretion of N-acetylglucosaminidase in subjects with impaired glucose tolerance.

N-acetylglucosaminidase (NAG) is a lysosomal enzyme produced by renal proximal tubular cells and has been widely used as a marker, which indicates a degree of renal tubular damage. An increase in urinary NAG excretion is though to result from the renal tubular damage. The aim of this study was to evaluate whether even mild hyperglycemia causes an increase in urinary excretion of NAG, which is a renal tubular protein. We examined urinary NAG excretion in overnight urine in 22 Japanese men with impaired glucose tolerance (IGT) for more than two years (IGT group) and 41 healthy control subjects matched in age, gender, BMI and blood pressure (control group). Urinary NAG excretion levels of IGT group and control group were 2.89 (1.23-7.97) and 2.22 (0.60-4.93) U/g creatinine, median (range), respectively. The IGT group showed significantly higher urinary excretion of NAG compared to the control group (p < 0.01). Several studies have indicated that plasma proteins filtered through the glomerular capillary may have intrinsic renal toxicity. Recently, we have reported that urinary excretion of plasma proteins (ceruloplasmin, IgG4 and IgG) with molecular radii of approximately 45-55 A is increased in subjects with IGT compared to healthy control subjects with normal glucose tolerance. Considering the present result together with our recent finding, we suggest that increased urinary excretion of NAG in the mildly hyperglycemic subjects may be due to the adverse effects of the plasma proteins highly filtered through the glomerular capillary on tubular cells.

Acetylglucosaminidase↗