Effects of Magnesium on Calcium Absorption in the Small Intestine of Goat and Sheep in vitro

We previously demonstrated that feeding a highly fermentable and water-soluble dietary fibre, guar-gum hydrolysate (GGH) increased intestinal absorption of insoluble Ca salts in total-gastrectomized rats. In the present study, we examined the effects of feeding a less fermentable and water-soluble fibre, polydextrose (PD), on Ca absorption and bone mineralization in the normal and total-gastrectomized rats in comparison with the effects of GGH. Apparent Ca absorption was severely lowered by gastrectomy, and PD feeding (50 g/kg diet) partially restored the reduction of Ca absorption similarly to GGH feeding (50 g/kg diet). PD feeding also increased the Ca absorption in normal rats, but not GGH feeding. Femur Ca concentration was reduced with gastrectomy. Feeding PD for 21 d increased the bone Ca concentration in both normal and gastrectomized rats, but GGH feeding did not. In rats fed PD, pH of the caecal contents was lower than in rats fed fibre-free and GGH diets; however, soluble Ca concentration in the caecal contents was not different between the diet groups. Short-chain fatty acid concentrations were much lower in the PD groups than in the GGH groups. We also examinedin vitroCa absorption by using everted sacs of the small intestine. Addition of PD to the serosal medium of the ileal sacs increased Ca absorption, but addition of GGH did not. These results suggest that the small intestine rather than the large intestine is responsible for the increase in Ca absorption in rats fed PD, and suggests that the mechanism for the increase by PD may be different from that by GGH.

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Influence of vitamin D on calcium absorption in the chick

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1962.203.3.497 ◽

1962 ◽

Vol 203 (3) ◽

pp. 497-505 ◽

Cited By ~ 40

Author(s):

J. D. Sallis ◽

E. S. Holdsworth

Keyword(s):

Vitamin D ◽

Small Intestine ◽

Calcium Transport ◽

Calcium Absorption ◽

Metabolic Inhibitors ◽

Hydroxyl Groups ◽

Oxidation Reduction ◽

Active Calcium

The site of absorption of Ca45 was studied in rachitic chicks and rachitic chicks given vitamin D3. Vitamin D3 markedly increases absorption from the small intestine and, in vivo, similar amounts of calcium are absorbed along the entire small intestine. With everted gut sacs, the distal third of the small intestine transported much more calcium than did the duodenal and middle sections. Thus, interpretations of in vitro results may not always depict the natural in vivo process. Vitamin D2 had little activity in the chick, but AT-10 series 2 and AT-10 series 3 were almost as active as vitamin D3 for calcium transport. These results suggest an "active carrier" may be formed by addition of hydrogen or hydroxyl groups to the opened ring B of vitamin D, giving a carrier capable of reversible oxidation-reduction or keto-enol tautomerism. Using metabolic inhibitors, active calcium transport in vitro relied on glycolysis for its energy supply. The transport was independent of the sodium pump.

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Electron probe x-ray microanalysis and electron microscopy of amino acid absorption and transport by the small intestine: inhibition by chemical poisons and correlation to the elemental composition of the epithelial cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100142311 ◽

1986 ◽

Vol 44 ◽

pp. 134-135

Author(s):

A. J. Tousimis

Keyword(s):

Small Intestine ◽

Amino Acid ◽

Epithelial Cells ◽

Elemental Composition ◽

Isotope Labeling ◽

Structural Components ◽

X Ray ◽

Human Small Intestine ◽

Transport Studies

The elemental composition of amino acids is similar to that of the major structural components of the epithelial cells of the small intestine and other tissues. Therefore, their subcellular localization and concentration measurements are not possible by x-ray microanalysis. Radioactive isotope labeling: I131-tyrosine, Se75-methionine and S35-methionine have been successfully employed in numerous absorption and transport studies. The latter two have been utilized both in vitro and vivo, with similar results in the hamster and human small intestine. Non-radioactive Selenomethionine, since its absorption/transport behavior is assumed to be the same as that of Se75- methionine and S75-methionine could serve as a compound tracer for this amino acid.

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Evaluation of the Impact of Excipients on Albendazole Concentrations in Upper Small Intestine Using an In Vitro Biorelevant Gastrointestinal Transfer (BioGIT) System

10.26226/morressier.57d6b2bbd462b8028d88e13f ◽

2016 ◽

Author(s):

Maria Vertzoni

Keyword(s):

Small Intestine ◽

The Impact

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Generation of tetracycline-controllable CYP3A4-expressing Caco-2 cells by the piggyBac transposon system

Scientific Reports ◽

10.1038/s41598-021-91160-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Moe Ichikawa ◽

Hiroki Akamine ◽

Michika Murata ◽

Sumito Ito ◽

Kazuo Takayama ◽

...

Keyword(s):

Small Intestine ◽

Drug Absorption ◽

Cell Model ◽

Negative Effects ◽

Piggybac Transposon ◽

Drug Metabolizing Enzyme ◽

Metabolizing Enzyme ◽

Cyp3a4 Expression

AbstractCaco-2 cells are widely used as an in vitro intestinal epithelial cell model because they can form a monolayer and predict drug absorption with high accuracy. However, Caco-2 cells hardly express cytochrome P450 (CYP), a drug-metabolizing enzyme. It is known that CYP3A4 is the dominant drug-metabolizing enzyme in human small intestine. In this study, we generated CYP3A4-expressing Caco-2 (CYP3A4-Caco-2) cells and attempted to establish a model that can simultaneously evaluate drug absorption and metabolism. CYP3A4-Caco-2 cells were generated by piggyBac transposon vectors. A tetracycline-controllable CYP3A4 expression cassette (tet-on system) was stably transduced into Caco-2 cells, thus regulating the levels of CYP3A4 expression depending on the doxycycline concentration. The CYP3A4 expression levels in CYP3A4-Caco-2 cells cultured in the presence of doxycycline were similar to or higher than those of adult small intestine. The CYP3A4-Caco-2 cells had enough ability to metabolize midazolam, a substrate of CYP3A4. CYP3A4 overexpression had no negative effects on cell proliferation, barrier function, and P-glycoprotein activity in Caco-2 cells. Thus, we succeeded in establishing Caco-2 cells with CYP3A4 metabolizing activity comparable to in vivo human intestinal tissue. This cell line would be useful in pharmaceutical studies as a model that can simultaneously evaluate drug absorption and metabolism.

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Absorption of lactulose from mammalian gastrointestinal tract

British Journal Of Nutrition ◽

10.1079/bjn19790010 ◽

1979 ◽

Vol 41 (1) ◽

pp. 47-51 ◽

Cited By ~ 8

Author(s):

D. F. Evered ◽

F. Sadoogh-Abasian

Keyword(s):

Small Intestine ◽

Calcium Ions ◽

Clinical Evidence ◽

Buccal Cavity ◽

Rat Small Intestine ◽

Sodium Ions ◽

Mode Of Transport ◽

Poor Absorption

1. The disaccharide lactulose (galactosyl-β-1,4-fructose) was poorly absorbed from rat small intestine in vitro and human mouth in vivo.2. These results confirm indirect clinical evidence of poor absorption from the intestine.3. The presence of calcium ions, or absence of sodium ions, had no effect on lactulose absorption from the buccal cavity.4. The presence of ouabain, or absence of Na+, did not decrease the absorption of lactulose from small intestine.5. It is thought that the mode of transport, in both instances, is by passive diffusion with the concentration gradient.

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Porcine Milk-Derived Small Extracellular Vesicles Promote Intestinal Immunoglobulin Production through pIgR

Animals ◽

10.3390/ani11061522 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1522

Author(s):

Bin Zeng ◽

Hailong Wang ◽

Junyi Luo ◽

Meiying Xie ◽

Zhengjiang Zhao ◽

...

Keyword(s):

Small Intestine ◽

Extracellular Vesicles ◽

Immunoglobulin A ◽

Luciferase Reporter ◽

Epithelial Cell Line ◽

Intestinal Immunity ◽

In Vivo Experiments ◽

Porcine Milk

Secretory immunoglobulin A (SIgA) plays an important role in gut acquired immunity and mucosal homeostasis. Breast milk is the irreplaceable nutritional source for mammals after birth. Current studies have shown the potential functional role of milk-derived small extracellular vesicles (sEVs) and their RNAs cargo in intestinal health and immune regulation. However, there is a lack of studies to demonstrate how milk-derived sEVs affect intestinal immunity in recipient. In this study, through in vivo experiments, we found that porcine milk small extracellular vesicles (PM-sEVs) promoted intestinal SIgA levels, and increased the expression levels of polymeric immunoglobulin receptor (pIgR) both in mice and piglet. We examined the mechanism of how PM-sEVs increased the expression level of pIgR in vitro by using a porcine small intestine epithelial cell line (IPEC-J2). Through bioinformatics analysis, dual-luciferase reporter assays, and overexpression or knockdown of the corresponding non-coding RNAs, we identified circ-XPO4 in PM-sEVs as a crucial circRNA, which leads to the expression of pIgR via the suppression of miR-221-5p in intestinal cells. Importantly, we also observed that oral administration of PM-sEVs increased the level of circ-XPO4 and decreased the level of miR-221-5p in small intestine of piglets, indicating that circRNAs in milk-derived sEVs act as sponge for miRNAs in recipients. This study, for the first time, reveals that PM-sEVs have a capacity to stimulate intestinal SIgA production by delivering circRNAs to receptors and sponging the recipient’s original miRNAs, and also provides valuable data for insight into the role and mechanism of animal milk sEVs in intestinal immunity.

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