scholarly journals Dietary ascorbic acid lowers the concentration of soluble copper in the small intestinal lumen of rats

1994 ◽  
Vol 71 (5) ◽  
pp. 701-707 ◽  
Author(s):  
G. J. Van Den Berg ◽  
S. YU ◽  
A. G. Lemmens ◽  
A. C. Beynen
Keyword(s):  
Ascorbic Acid ◽  
Small Intestine ◽  
Liquid Phase ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Intestinal Lumen ◽  
Distal Intestine ◽  
Small Intestinal ◽  
Ascorbic Acid Supplementation

We tested the hypothesis that ascorbic acid in the diet of rats lowers the concentration of soluble Cu in the small intestine, causing a decrease in apparent Cu absorption. Male rats were fed on diets adequate in Cu (5 mg Cu/kg) without or with 10 g ascorbic acid/kg. The diet with ascorbic acid was fed for either 6 or 42 d. Ascorbic acid depressed tissue Cu concentrations after a feeding period of 42, but not after 6 d. Dietary ascorbic acid lowered apparent Cu absorption after 6, but not after 42 d. The lowering of tissue Cu concentrations after long-term ascorbic acid feeding may have increased the efficiency of Cu absorption, and thus counteracted the inhibitory effect of ascorbic acid. Dietary ascorbic acid caused a significant decrease in the Cu concentrations in the liquid phase of both the proximal and distal parts of the small intestinal lumen. This effect was due to both a decrease in the amount of Cu in the liquid digesta and an increase in the volume of the liquid phase; only the latter effect for the distal intestine was statistically significant. We conclude that ascorbic acid supplementation lowers Cu absorption by decreasing the concentration of soluble Cu in the small intestine.

scholarly journals Dietary fructose v. glucose lowers ferrous-iron absorption in rats

1993 ◽  
Vol 70 (1) ◽  
pp. 171-178 ◽  
Author(s):  
I. A. Brouwer ◽  
A. G. Lemmens ◽  
A. C. Beynenl
Keyword(s):  
Small Intestine ◽  
Liquid Phase ◽  
Cell Volume ◽  
Packed Cell Volume ◽  
Ferrous Iron ◽  
Iron Absorption ◽  
Female Rats ◽  
Intestinal Lumen ◽  
Distal Intestine ◽  
Dietary Fructose

The effect of dietary fructose v. glucose on Fe solubility in the small intestine and apparent Fe absorption was studied in rats. Female rats were fed for 4 weeks on low-Fe (10 mg Fe/kg) or normal-Fe (40 mg Fe/kg) diets containing either fructose or glucose (709·4 g monosaccharide/kg). Fe was added to the diets in the form of FeSO4. The low-Fe diets did not lower levels of haemoglobin and packed cell volume, but significantly lowered Fe concentration and Fe mass in the liver, kidney and spleen. Fructose v. glucose also lowered Fe concentrations in these organs, but did not alter absolute Fe contents. Low Fe intake reduced the amount of Fe in the intestinal lumen. The total amount of Fe and Fe concentration in the liquid phase of the proximal intestinal lumen were depressed by fructose irrespective of Fe intake. Fructose also lowered the amount of Fe in the liquid phase of the distal intestine. In keeping with these observations, dietary fructose significantly lowered apparent absorption of Fe at the two levels of Fe intake. Decreasing the intake of Fe raised the percentage of apparent Fe absorption.

Endogenous cholecystokinin does not decrease food intake or gastric emptying in fasted rats

1989 ◽  
Vol 257 (6) ◽  
pp. R1462-R1466 ◽  
Author(s):  
G. P. Smith ◽  
D. Greenberg ◽  
J. D. Falasco ◽  
A. A. Avilion ◽  
J. Gibbs ◽  
...  
Keyword(s):  
Small Intestine ◽  
Gastric Emptying ◽  
Food Intake ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Sham Feeding ◽  
Decrease Food Intake ◽  
Negative Results ◽  
Small Intestinal ◽  
Fasted Rats

To investigate the hypothesized inhibitory effect of cholecystokinin (CCK) released from the small intestine on food intake and gastric emptying, we infused soybean trypsin inhibitor (STI) into the stomach or duodenum of male rats deprived of food for 17 h. Intraduodenal infusions of STI (100-200 mg) before real or sham feeding, or during sham feeding, had no effect on food intake. Intragastric infusions of STI (100-200 mg) also had no effect on gastric emptying. Identical infusions of STI, however, increased bioassayable plasma CCK six to ninefold. The failure of endogenous, small intestinal CCK released by STI to decrease food intake or to decrease gastric emptying is evidence against the hypothesis that the inhibitions of food intake and of gastric emptying are physiological functions of small intestinal CCK in food-deprived rats. In contrast to the negative results with STI, administration of exogenous CCK-8 (2-4 micrograms/kg ip) significantly inhibited food intake and gastric emptying despite producing smaller increases of plasma CCK than STI produced. The reason for the differential effects of exogenous and endogenous CCK is not clear and requires further investigation.

Studies on the anthelmintic activity of hexylresorcinol and tetrachlorethylene

Parasitology ◽  
1944 ◽  
Vol 36 (1-2) ◽  
pp. 98-109 ◽  
Author(s):  
W. P. Rogers
Keyword(s):  
Ascorbic Acid ◽  
Small Intestine ◽  
Bile Salts ◽  
Test Organism ◽  
Anthelmintic Activity ◽  
Intestinal Lumen ◽  
Rat Small Intestine ◽  
Inhibiting Factors ◽  
Intestinal Fluids ◽  
Rate Of Movement

1. A method for examining conditions governing anthelmintic activity in the small intestine is described. Nippostrongylus muris in the rat was the test organism and hexylresorcinol and C2C14 were the drugs examined.2. The efficiency of hexylresorcinol was reduced by 50% in 1% sodium tauroglycocholate which reached a concentration of 1·3% in the rat small intestine. The adsorption of this drug on mucin reduced its concentration in intestinal fluids and prevented penetration to parasites under mucus. These inhibiting factors account for the inactivity of hexylresorcinol in the rat.3. Tetrachlorethylene, which stimulated N. muris to leave mucus and enter fluids in the intestinal lumen, was not inhibited by bile salt and was found to act rapidly in the rat.4. Sodium laurate activated hexylresorcinol more efficiently than sodium oleate at pH. 6·5. Both soaps showed intrinsic anthelmintic properties.5. The results obtained in examining the rate of movement of fluids down the intestine and the effects of detergents, bile salts, mucin and ascorbic acid on drug activity are discussed.

scholarly journals Lack of Small Intestinal Dysbiosis Following Long-Term Selective Inhibition of Cyclooxygenase-2 by Rofecoxib in the Rat

Cells ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 251 ◽  
Author(s):  
Bernadette Lázár ◽  
Gábor Brenner ◽  
András Makkos ◽  
Mihály Balogh ◽  
Szilvia László ◽  
...  
Keyword(s):  
Selective Inhibition ◽  
Mucosal Damage ◽  
Inhibitory Effect ◽  
Intestinal Dysbiosis ◽  
Bowel Diseases ◽  
Direct Inhibitory Effect ◽  
Cox 2 ◽  
Small Intestinal

Intestinal dysbiosis is linked to numerous gastrointestinal disorders, including inflammatory bowel diseases. It is a question of debate if coxibs, selective inhibitors of cyclooxygenase (COX)-2, cause dysbiosis. Therefore, in the present study, we aimed to determine the effect of long-term (four weeks) selective inhibition of COX-2 on the small intestinal microbiota in the rat. In order to avoid mucosal damage due to topical effects and inflammation-driven microbial alterations, rofecoxib, a nonacidic compound, was used. The direct inhibitory effect of rofecoxib on the growth of bacteria was ruled out in vitro. The mucosa-sparing effect of rofecoxib was confirmed by macroscopic and histological analysis, as well as by measuring the intestinal levels of cytokines and tight junction proteins. Deep sequencing of bacterial 16S rRNA revealed that chronic rofecoxib treatment had no significant influence on the composition and diversity of jejunal microbiota. In conclusion, this is the first demonstration that long-term selective inhibition of COX-2 by rofecoxib does not cause small intestinal dysbiosis in rats. Moreover, inhibition of COX-2 activity is not likely to be responsible per se for microbial alterations caused by some coxibs, but other drug-specific properties may contribute to it.

SOME ANTIGONADOTROPHIC EFFECTS OF MELATONIN-FREE BOVINE PINEAL EXTRACTS IN RATS

1974 ◽  
Vol 76 (3) ◽  
pp. 438-448 ◽  
Author(s):  
Richard J. Orts ◽  
Bryant Benson ◽  
Byron F. Cook
Keyword(s):  
Gel Filtration ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Reproductive Parameters ◽  
Castrate Male ◽  
Serum Luteinizing Hormone ◽  
Bovine Pineal Extracts ◽  
Modifying Effect ◽  
Pineal Extracts

ABSTRACT Studies were made to determine if a substance other than melatonin was present in bovine pineal gland extracts which possessed properties inhibitory to some gonadotrophin-dependent reproductive parameters in rats. Bovine pineal extracts were partially purified by organic solvent extraction or by ultrafiltration and gel-filtration to exclude melatonin. When administered to rats, the extracts inhibited compensatory ovarian hypertrophy, delayed vaginal opening time and reduced the incidence of constant oestrus. Either of the melatonin-free extracts reduced significantly the concentration of serum luteinizing hormone (LH) in long-term castrate male rats. The data suggest that some substance other than melatonin present in bovine pineal glands has a modifying effect on the reproductive parameters observed probably due to its inhibitory effect on LH.

Effect of ascorbic acid supplementation on testicular steroidogenesis and germ cell death in cadmium-treated male rats

2004 ◽  
Vol 221 (1-2) ◽  
pp. 57-66 ◽  
Author(s):  
Ronojoy Sen Gupta ◽  
Jisun Kim ◽  
Cynthia Gomes ◽  
Sungdug Oh ◽  
Juran Park ◽  
...  
Keyword(s):  
Cell Death ◽  
Ascorbic Acid ◽  
Germ Cell ◽  
Male Rats ◽  
Acid Supplementation ◽  
Treated Male ◽  
Testicular Steroidogenesis ◽  
Ascorbic Acid Supplementation

Evidence that neuronally released vasoactive intestinal polypeptide inhibits the release of serotonin from enterochromaffin cells of the guinea pig small intestine

1991 ◽  
Vol 124 (2) ◽  
pp. 203-207 ◽  
Author(s):  
Kurt Racké ◽  
Harald Schwörer ◽  
Denis V. Agoston ◽  
Heinz Kilbinger
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Vasoactive Intestinal Polypeptide ◽  
Inhibitory Effect ◽  
Good Evidence ◽  
Muscarine Receptors ◽  
Intestinal Segments ◽  
Hydroxyindoleacetic Acid ◽  
Small Intestinal ◽  
Intestinal Polypeptide

Abstract. Isolated small intestinal segments of the guinea pig were arterially perfused and the release of serotonin (5-hydroxytryptamine) and 5-hydroxyindoleacetic acid into the portal venous effluent was determined by HPLC with electrochemical detection. Test substances were intra-arterially applied. The muscarine receptor agonist oxotremorine (1 μmol/l inhibited the release of 5-hydroxytryptamine by about 50%. In the presence of the neurotoxin tetrodotoxin, oxotremorine enhanced the release of 5-hydroxytryptamine by 145%, indicating that the inhibitory effect of oxotremorine was mediated by the release of a neurotransmitter. Exogenous vasoactive intestinal polypeptide ( 1-100 pmol/l inhibited the release of 5-hydroxytryptamine by about 50%, an effect antagonized by a specific antibody to vasoactive intestinal polypeptide. This antibody to vasoactive intestinal polypeptide, on its own, had no effect on the release of 5-hydroxytryptamine. However, it prevented the inhibitory effect of oxotremorine. In the presence of the antibody to vasoactive intestinal polypeptide, unlike in the presence of tetrodotoxin, oxotremorine did not stimulate the release of 5-hydroxytryptamine. In conclusion, activation of neuronal muscarine receptors in the guinea pig small intestine enhances the release of several neurotransmitters which can inhibit the release of 5-hydroxytryptamine. The present experiments provide good evidence that vasoactive intestinal polypeptide is one of them.

Sign in / Sign up

Export Citation Format

Share Document