A Combination of a Dairy Product Fermented by Lactobacilli and Galactooligosaccharides Shows Additive Effects on Mineral Balances in Growing Rats with Hypochlorhydria Induced by a Proton Pump Inhibitor

This study aimed to investigate the effects of a combination of a dairy product fermented by lactobacilli (DFL) and galactooligosaccharides (GOS) on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor (PPI). Three-week-old male rats were assigned to receive one of six diets: a control diet, control diets containing 1.6 or 5.0 % GOS, a DFL diet and DFL diets containing 1.6 or 5.0 % GOS for 9 days. From day 5 of the feeding period, half of the rats fed with control diets were subcutaneously administered with saline, whereas the remaining rats were administered with PPI for 5 days. Calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe) and zinc (Zn) balances were determined from days 6 to 9. PPI administration significantly decreased the apparent absorption of Ca and Fe and increased urinary P excretion, resulting in decreased Ca, Fe and P retention. GOS dose-dependently increased the apparent absorption of Ca, Mg and Fe and urinary Mg excretion and decreased urinary P excretion. DFL significantly increased the apparent absorption of Ca and Mg and urinary Mg excretion. The combination of DFL and GOS additively affected these parameters, resulting in increased Ca, P and Fe retention, and it further increased the apparent absorption and retention of Zn at 5.0 % GOS. In conclusion, the combination of DFL and GOS improves Ca, P and Fe retention in an additive manner and increases the Zn retention in growing rats with hypochlorhydria induced by PPI.     

The fate of cyclamate in man and other species

1. (14)C-labelled cyclamate has been administered to guinea pigs, rabbits, rats and humans. When given orally to these species on a cyclamate-free diet, cyclamate is excreted unchanged. In guinea pigs some 65% of a single dose is excreted in the urine and 30% in the faeces, the corresponding values for rats being 40 and 50%, for man, 30-50% and 40-60%, and for rabbits, 90 and 5%, the excretion being over a period of 2-3 days. 2. Cyclamate appears to be readily absorbed by rabbits but less readily by guinea pigs, rats and humans. 3. If these animals, including man, are placed on a diet containing cyclamate they develop the ability to convert orally administered cyclamate into cyclohexylamine and consequently into the metabolites of the latter. The extent to which this ability develops is variable, the development occurring more readily in rats than in rabbits or guinea pigs. In three human subjects, one developed the ability quite markedly in 10 days whereas two others did not in 30 days. Removal of the cyclamate from the diet caused a diminution in the ability to convert cyclamate into the amine. 4. In rats that had developed the ability to metabolize orally administered cyclamate, intraperitoneally injected cyclamate was not metabolized and was excreted unchanged in the urine. The biliary excretion of injected cyclamate in rats was very small, i.e. about 0.3% of the dose. 5. The ability of animals to convert cyclamate into cyclohexylamine appears to depend upon a continuous intake of cyclamate and on some factor in the gastrointestinal tract, probably the gut flora.     

Effect of glucagon on phenylalanine metabolism and phenylalanine-degrading enzymes in the rat

Glucagon administered subcutaneously to rats for 10 days had no significant effect on liver phenylalanine hydroxylase activity, but induced liver dihydropteridine reductase more than twofold. In rats administered a phenylalanine load orally, glucagon treatment stimulated oxidation and depressed urinary phenylalanine excretion. These responses could not be related to an effect of glucagon on hepatic tyrosine-alpha-oxoglutarate aminotransferase activity. Even in rats with phenylalanine hydroxylase activity depressed to 50% of control values by p-chlorophenylalanine administration, glucagon treatment increased the phenylalanine-oxidation rate substantially. Although hepatic phenylalanine-pyruvate aminotransferase was increased tenfold in glucagon-treated rats, glucagon treatment did not increase urinary excretion of phenylalanine transamination products by rats given a phenylalanine load. Glucagon treatment did not affect phenylalanine uptake by the gut or liver, or the liver content of phenylalanine hydroxylase cofactor. It is suggested that dihydropteridine reductase is the rate-limiting enzyme in phenylalanine degradation in the rat, and that glucagon may regulate the rate of oxidative phenylalanine metabolism in vivo by promoting indirectly the maintenance of the phenylalanine hydroxylase cofactor in its active, reduced state.     

The influence of cadmium on the biliary excretion of eosine and bromsulphthalein and on microsomal monooxygenase activities in the rat

Cadmium sulfate x 8/3 H2O (0.3, 0.6, 1.5 and 2.0 mg/kg) administered simultaneously with eosine and bromsulphthalein (120 mumol/kg i.v.) did not significantly change the biliary excretion of the dyes. After a 3 days pretreatment with 2.0 mg/kg CdSO4 i.p. a body weight loss and an increase in the relative liver weight when calculated on body weight were observed together with an enhanced bile flow, but the excretion of the dyes was not markedly influenced. Ethylmorphine N-demethylation and ethoxycoumarin O-deethylation activities as well as microsomal cytochrome P-450 concentration were diminished by about 50%. It can be concluded that in male rats the hepatic microsomal monooxygenase system is more sensitive towards cadmium than the hepatic transport system for organic anions.     

Reserpine inhibits release of vasopressin from the neural lobe of the pituitary in dehydrated rats

Summary The effects of reserpine on the osmotically induced release of pituitary vasopressin were studied (i) by measuring the urinary excretion and the vasopressin content of the neural lobe of the pituitary, and (ii) by examining the ultrastructural morphology of axons in the neural lobe of dehydrated rats. After water deprivation for two days, control rats displayed characteristic antidiuretic response including a 75% reduction of urinary excretion and a sixfold decrease in vasopressin content of the neural lobe associated with a dramatic depletion of neurosecretory granules in corresponding axons. In contrast, when they received two daily injections of reserpine, animals dehydrated for two days showed both urinary excretion and vasopressin contents in the neural lobe that remained at levels comparable to those measured in the normally hydrated rats. Additionally, neural-lobe axons of such dehydrated, reserpine-treated rats displayed a normal amount of neurosecretory granules. These data indicate that reserpine inhibits release of vasopressin from the neural lobe and favour the concept of a facilitatory role of the catecholaminergic innervation in the control of hypothalamo-neurohypophysial vasopressin-secreting neurons.     

Influence of a cecal volume-reducing intestinal microflora on the excretion and entero-hepatic circulation of steroids and bile acids

From mouse fecal material we have isolated four strictly anaerobic bacteria which, when associated with germfree mice or rats, reduced the cecal volume by 80 and 60%, respectively. This cecal volume-reducing flora did not metabolize estrone-3-sulfate, taurolithocholate-3-sulfate or taurolithocholate but gnotobiotic rats associated with this particular flora (CRF-rats) excreted these compounds faster in feces plus urine than did germfree rats. The time needed for 50% excretion (t1/2) of orally administered estrone-3-sulfate was 32 h in germfree rats versus 13 h in CRF rats; for intraperitoneally injected taurolithocholate-3-sulfate the t1/2 was 63 h in germfree versus 17 h in CRF rats and for taurolithocholate the t1/2 was 199 h in germfree and 96 h in CRF rats. Association of germfree rats with the cecal volume-reducing flora did not change the cecal absorption rate of estrone-3-sulfate, but shortened the 50% small intestinal transit time of [14C]PEG from 10 to 3 h; a value also found in conventional rats. These results stress the important influence of the intestinal microflora on the absorption and excretion of steroids via its effect on the physiology of the whole intestinal tract and point to the deficiencies inherent to the use of germfree animals in excretion studies.     

Effects of a chitosan intake on the fecal excretion of dioxins and fat in rats

We evaluated the effects of the intake of various dietary fibers on the fecal excretion of dioxins in rats. The rats were fed five types of dietary fiber diets, including a chitosan diet and control diet, for 20 d and then dioxins (120 ng/rat) were orally administered on day 15. The excretion of fecal dioxins was significantly higher in the chitosan group than in the control group, and dioxin excretion was positively correlated with fecal fat excretion. A comparison of the different types of chitosan showed that the efficacy of chitosan for fecal fat excretion was partly related to its viscosity. The chitosan intake promoted fecal dioxin excretion when the rats were exposed to highly toxic dioxins, and this excretion of fecal dioxins was related to the fecal fat excretion, suggesting that chitosan might be useful for reducing the adverse effects caused by lipophilic xenobiotics.     

Influence of an estrone-desulfating intestinal flora on the enterohepatic circulation of estrone-sulfate in rats

The fecal and urinary excretion of orally administered [4-14C]estrone-3-sulfate was studied in germfree (GF) rats, conventional (CV) rats and gnotobiotic rats selectively associated with estrone-desulfating and/or cecal-volume reducing microorganisms. The time required to excrete 50% of the total label recovered (t 1/2) was 22 h in CV rats vs 32 h in GF rats. Gnotobiotic rats selectively associated with a cecal volume-reducing flora (CRF rats) excreted the label even faster (t 1/2 = 13 h) than CV rats. Association of GF rats as well as CRF rats with estrone-desulfating microorganisms (termed S1 + S2 + R9 rats and CRF + S1 + S2 + R9 rats, respectively) led to a slower excretion of labeled products (t 1/2 = 38 h in S1 + S2 + R9 rats and t 1/2 = 27 h in CFR + S1 + S2 + R9 rats). Intestinal microbial desulfation also increased the relative part of the urinary excretion from 4% in GF rats to 8% in S1 + S2 + R9 rats and from 3% in CRF rats to 9% in CFR + S1 + S2 + R9 rats. We conclude that intestinal microbial desulfation enhances the enterohepatic circulation of orally administered estrone-3-sulfate.     

Influence of spironolactone on urinary prostaglandin E2 and kinin excretion in rats

Spironolactone was administered to spontaneously hypertensive rats (SHRs) in order to examine the urinary excretions of prostaglandin E2 (PGE2) and kinin. Thirteen SHRs were divided into 2 groups: 0.1 ml of sesame oil was administered to one group (the spironolactone-lactone-untreated group, n = 6) and 20 mg of spironolactone in 0.1 ml of sesame oil was administered to the other group (the spironolactone-treated group, n = 7) by the subcutaneous route for 10 days in succession. Determinations were then made of the body weight, blood pressure, urine volume, and excretion levels of Na, K, kinin and PGE2 in the 24-hour urine. After the animals had been killed by decapitation, blood samples were drawn for determination of the plasma renin activity (PRA). The results obtained indicated decreased blood pressure and increased urinary Na excretion in the spironolactone-treated group. On the other hand, the PGE2 excretion level in the 24-hour urine decreased markedly immediately after administration of spironolactone (p less than 0.05) and was maintained at lower levels up to the end of the experiment. However, the 24-hour urinary kinin levels showed similar changes in both the spironolactone-treated group and the untreated group with no significant difference between them. These findings suggest that spironolactone has a suppressive effect on urinary PGE2 excretion, the activity of which is not mediated by kinin production in the kidneys but is the result of a direct action of spironolactone itself.     

Reversible hepatic black pigmentation and enzyme alteration induced by prolonged feeding of high dose of crocin dyes in rats

Crocin dyes, isolated from Gardenia jasminodes, did not affect hepatic function when they were orally administered to rats in a daily dose of 50 mg/kg for 8 days, but could induce acute hepatic discoloration. A high dosage of 100 mg/kg for 2 weeks could induce both hepatic damage and black pigmentation, but a lower dose of 100 mg/kg for 40 days did not. Rats fed on diet containing 1% of crocin dyes for four months were shown to have mild hepatic functional disorders and pigmentation. The black pigmentation of the liver and the acute hepatic damage associated with the discoloration were completely reversible. During the period of hepatic pigmentation caused by high dose of crocin dyes, the urine had abnormally increased porphyrin excretion and tended to display a blackish green color. The skin also appeared purplish black. The mechanism of black pigmentation seemed to correlate with the gradual accumulation of crocin dyes. In summary, the crocin dyes have a very low toxicity in rats even in high experimental dosage which would hardly happen in human practice. It is therefore suggested that the crocin dyes are safe for coloring foods.     

Effects of 8 bromo-cyclic GMP on cyclic AMP levels in urine and tissues of hypothyroid rats.

The effects of 8-bromo-guanosine 3', 5' cyclic monophosphate (8Brcyclic GMP) on the levels of cyclic AMP in urine, brain, liver, and muscle were determined in hypothyroid rats. Cyclic AMP urinary levels were significantly lower in untreated hypothyroid rats than in normal rats, and when hypothyroid rats were treated with replacement thyroxine, urinary cyclic AMP returned to normal after six days of treatment. Hypothyroid rats treated with 8Brcyclic GMP, 30 mg/kg body weight subcutaneously every 12 hours exhibited a biphasic response. From days 2 through 4 of treatment, cyclic AMP excretion rose to approximately 2.5 times normal levels. Subsequently, the cyclic AMP excretion returned to hypothyroid levels and remained low throughout the rest of the treatment period. Tissue cyclic AMP levels in hypthyroid rats treated with 8Br-cyclic GMP were increased in comparison to those of untreated hypothyroid rats. Increase in brain was 134%, in liver 55%, and in muscle 42%. We conclude from these studies that 8Br-cyclic GMP can significantly alter cyclic AMP levels in hypothyroid rats.     

The effect of lincomycin on the excretion of diethylstilbestrol and its uterotrophic action in rats.

The enterohepatic circulation of diethylstilbestrol (DES) has been shown to be extensive and to be dependent on enteric β-glucuronidase activity for release of absorbable DES from its nonabsorbable glucuronide excreted in bile. A regimen of the antibiotic lincomycin has been shown in rats to markedly reduce enteric β-glucuronidase activity, intestinal hydrolysis of C¹⁴-DES-glucuronide and absorption of radioactivity. Studies were therefore performed to determine if this lincomycin regimen, by reducing enterohepatic circulation of DES, would alter systemic effects of DES such as uterine weight gain in ovariectomized rats. The lincomycin regimen consisted of 25 mg twice daily by gastric intubation on days 1–4 and 500 mg/l in drinking water on days 1–7. Lincomycin-treated and control rats were injected s.c. with DES (1.6 or 5.0 μg/kg/day) on days 4–6 and sacrificed on day 7 for measurement of uterine weight; the injection on day 4 consisted on monoethyl-l-C¹⁴-DES. Lincomycin did not change the uterotrophic effect of DES. The regimen did, however, reduce the urinary excretion of radioactivity and increase the fecal excretion of glucuronide conjugates, consistent with reduced enterohepatic circulation of DES. In a separate study, bile from rats given DES s.c. was administered into the cecum of lincomycin-treated and control rats; whereas 31.8% of the cecal dose was excreted in the bile of controls, only 1.9% was excreted in lincomycin-treated rats, indicating the marked reduction of DES enterohepatic circulation produced by lincomycin. These findings suggest that the enterohepatic circulation of DES does not significantly contribute to its systemic effects.     

Effect of vitamin K on the excretion of cholesterol and degradation products in rats

The effects of vitamin K₁ and K₂ on the fecal excretion of the radioactivity from the rats given cholesterol-4^?14C have been studied.There was a significant increase in the radioactivity excretion by the administration of vitamin K, and 23.3–31.5% of the total radioactivity injected were excreted in a week in the feces of the rats administered vitamin K, while 16.3–17.6% in the control animals.The change was due entirely to the increase in fecal bile acid excretion but no significant change was observed in neutral sterol output. The implications of these findings were discussed.     

Renal effects of dopamine and ANP in high volume expanded rats

Both dopamine (DA) and atrial natriuretic peptide (ANP) have been postulated to exert similar effects on the kidney, participating in the regulation of body fluid and sodium homeostasis. In the present study, experiments were performed in anesthetized and isotonic sodium chloride volume expanded rats. After acute volume expansion at 15 % of body weight during 30 min, glomerular filtration rate, urine output, sodium excretion, fractional sodium excretion, proximal and distal sodium excretion and blood pressure were measured. In additional groups we administered ANP or haloperidol or the combination of both to volume expanded animals. Blockade of DA receptors with haloperidol, attenuated diuretic and natriuretic responses to volume load. Proximal sodium excretion was not modified by haloperidol in all experimental groups of rats. Reduction in distal tubular excretion was induced by haloperidol in saline infusion expanded rat but not in ANP treated expanded animals. In conclusion, when exaggerated volume expansion is provoked, both DA and ANP exert renal tubular events, but ANP have a major central role in the regulation of renal sodium handling.     

Faecal Excretion Dynamic during Subacute Oral Exposure to Different Pb Species in Rattus norvegicus

Faecal excretion is a basic means of detoxification upon ingestion of Pb-contaminated feed. In order to determine a time course of Pb elimination after oral exposure to two different forms of this heavy metal (lead acetate vs. phyto-bound Pb), a feeding study was carried out in experimental rats using the Pb phyto-hyperaccumulator Pistia stratiotes as a model diet. The effect of starvation on Pb excretion was further studied in rats that were fed plant material. Twelve Pb doses (7 μg Pb/1 g BW) were administered orally over a 5-week period. Faeces samples were collected 24 and 72 h post-exposure. Inductively coupled plasma optical emission spectrometry and electrothermal absorption spectrometry methods were used for determination of heavy metal concentrations. Up to 53 % of ingested Pb was rapidly eliminated from the exposed rats via faeces within 24 h after exposure. Faecal excretion in exposed rats differed significantly when compared to that of the control group. Fasting before exposure reduced Pb excretion by up to 50 %. Faecal excretions of both examined Pb forms exhibited almost identical patterns. Considerable differences were revealed concerning total excretion levels; lead acetate was excreted in amount greater extent than those of phytobound Pb. Results of our study suggest that Pb forms occurring in the P. stratiotes tissues are absorbed through the gastrointestinal tract to a greater extent than Pb from lead acetate. Therefore, higher portions of ingested Pb can be available for potential accumulation in tissues of exposed subjects.     

Effect of dietary protein, alfalfa, and zeolite on excretory patterns of 5',5',7',7'-[3H]zearalenone in rats

A series of experiments was conducted to determine how dietary protein, alfalfa, or zeolite influence the excretory patterns of zearalenone (Z), a uterotropic mycotoxin synthesized by Fusarium fungi. Rats were fed diets containing 16.3% casein, 40% casein, 11.2% casein + 25% alfalfa, or 25% casein + 25% alfalfa. Also fed were diets containing 0, 1, 2, or 5% anion exchange zeolite. Tracer doses of [3H]Z were administered either as a constituent of the diet or as a topical application on the skin at the base of the skull. When Z was administered orally, no differences were seen in the fraction of the dose excreted in urine or feces as a result of varying dietary levels of alfalfa and protein. Topical doses resulted in rats fed 25% casein + 25% alfalfa or 40% casein excreting more Z in urine than those fed 25% alfalfa or 16.3% casein. Fecal excretion of Z was greatest for rats fed 25% casein + 25% alfalfa whereas rats fed 40% casein excreted more fecal Z than those fed 16.3% casein. Feeding Z to rats receiving dietary zeolite resulted in a positive correlation between dietary zeolite and fecal excretion of Z but a negative correlation with urinary excretion of Z. Topical administration of Z produced a positive correlation between dietary zeolite and fecal Z excretion but no effect on urinary excretion. It may be concluded that protein and alfalfa treatments alleviate Z toxicosis through increased metabolism whereas zeolite binds Z in the digestive tract to prevent absorption.     

Influence of triiodothyronine and dexamethasone on renal amino acid handling in rats loaded with various amino acid mixtures

Summary In adult female rats, the influence of dexamethasone or triiodothyronine on renal amino acid handling was investigated in amino acid loaded animals. Amino acids were administered intravenously as two mixtures, each containing four amino acids to overload amino acid reabsorption capacity. Bolus injections of both mixtures were followed by temporary increase in fractional excretion of the administered amino acids as well of the amino acids which were not covered in the mixtures. The administration of the two mixtures was followed by different interactions between various amino acid carriers.After dexamethasone pretreatment (60µg/100g b.wt. for 3 days, once daily) a stimulation of the renal amino acid handling could be shown. Triiodothyronine (20µg/100g b.wt. for 3 days, once daily) did not increase tubular reabsorption capacity for amino acids. It even increased fractional amino acid excretion in amino acid loaded rats as a sign of enhanced amino acid metabolism in the kidney and/or increased amino acid uptake into the tubular cells from the luminal site.     

Biliary metabolites of all-trans-retinoic acid in the rat

Biliary metabolites from physiological doses of all-trans-[10-3H]retinoic acid were examined in normal and vitamin A-deficient rats. The bile from normal and vitamin A-deficient rats contained approximately 60% of the administered dose following a 24-h collection period. However, vitamin A-deficient rats show a 6-h delay in the excretion of radioactivity compared to normal rats. Retinoyl-beta-glucuronide excretion was particularly sensitive to the vitamin A status of the rats. In normal rats, retinoyl-beta-glucuronide reached a maximum concentration of 235 pmol/ml of bile 2 h following the dose and then rapidly declined. Vitamin A-deficient rats show a relatively constant concentration of this metabolite (100-150 pmol/ml of bile) over a 10-h collection period. Retinoic acid excretion was low in both normal and deficient rats. The concentration of retinotaurine, a recently identified biliary metabolite, was approximately equal to retinoyl-beta-glucuronide in normal rats and appeared in the bile 2 h later than the glucuronide.     

The effect of iron on the excretion by rats of intratracheally administered plutonium-239

A study was made of the effect of ferric citrate on excretion of intratracheally administered plutonium-239. The preparation used permitted to increase the radionuclide excretion via the gastrointestinal tract by 1.8 times as compared to the control. The positive effect of the iron preparation was maximally displayed between days 4 and 11 following administration: the value of the increase was 2.2.     

Urinary metabolites of cis-9,10-methylene octadecanoic acid. cis-3,4-Methylene hexanedioic acid and related compounds.

cis-3,4-Methylene hexanedioic acid has been discovered in human urine. It has been isolated and identified by mass spectrometry and synthesis. The daily excretion in nine subjects on a free diet was 88 mumol/day (range, 32 to 144 mumol/day). cis-3,4-Methylene hexanedioic acid was given orally to a rat. About 90% of the dose was recovered unchanged in the urine within 24 h. Intragastric administration of cis-9,10-methylene [9,10-3H2]octadecanoic acid to rats gave four labeled urinary metabolites. The major one was cis-3,4-methylene hexanedioic acid, the others were 2,3-methylene pentanedioic acid and isomers of methylene heptanedioic acid and methylene octanedioic acid. Within 72 h, about 40% of the administered radioactivity could be recovered from the urine and another 40% from the carcass. About 20% of the recovered radioactivity was found to be water. Of the radioactivity administered to rats orally as cis-9,10-methylene [9,10-3H2]octadecanoic acid methyl ester, about 50% could be recovered from the lymph of the thoracic duct within 9 h. Intraperitoneal administration of cis-9,10-methylene octodecanoic acid methyl ester to rats gave the same metabolites. Of the given amount, 50 mol % could be recovered from the urine as cis-3,4-methylene hexanedioic acid and 19 mol % as homologues within 38 days.