scholarly journals Ontogeny of dipeptide uptake and peptide transporter 1 (PepT1) expression along the gastrointestinal tract in the neonatal Yucatan miniature pig

2012 ◽  
Vol 110 (2) ◽  
pp. 275-281 ◽  
Author(s):  
Matthew G. Nosworthy ◽  
Robert F. Bertolo ◽  
Janet A. Brunton
Keyword(s):  
Small Intestine ◽  
Age Groups ◽  
Peptide Transport ◽  
Peptide Transporter ◽  
Loop Model ◽  
Peptide Transporter 1 ◽  
Proximal Intestine ◽  
Dipeptide Uptake ◽  
Dipeptide Transport

The H+-coupled transporter, peptide transporter 1 (PepT1), is responsible for the uptake of dietary di- and tripeptides in the intestine. Using an in vivo continuously perfused gut loop model in Yucatan miniature pigs, we measured dipeptide disappearance from four 10 cm segments placed at equidistant sites along the length of the small intestine. Pigs were studied at 1, 2, 3 (suckling) and 6 weeks (post-weaning) postnatal age. Transport capability across the PepT1 transporter was assessed by measuring the disappearance of 3H-glycylsarcosine; real-time RT-PCR was also used to quantify PepT1 mRNA. Each of the regions of intestine studied demonstrated the capacity for dipeptide transport. There were no differences among age groups in transport rates measured in the most proximal intestine segment. Transport of 3H-glycylsarcosine was significantly higher in the ileal section in the youngest age group (1 week) compared with the other the suckling groups; however, all suckling piglet groups demonstrated lower ileal transport compared with the post-weaned pigs. Colonic PepT1 mRNA was maximal in the earliest weeks of development and decreased to its lowest point by week 6. These results suggest that peptide transport in the small intestine may be of importance during the first week of suckling and again with diet transition following weaning.

Effect of age on the secretory capacity of pig small intestine in vivo and in vitro

1990 ◽  
Vol 259 (3) ◽  
pp. G474-G480 ◽  
Author(s):  
G. T. McEwan ◽  
B. Schousboe ◽  
C. G. Nielsen ◽  
E. Skadhauge
Keyword(s):  
Small Intestine ◽  
Age Groups ◽  
Fluid Secretion ◽  
Similar Response ◽  
Ct Dose ◽  
Fluid Losses ◽  
Effect Of Age ◽  
Secretory Capacity

The effect of age on the secretory response of pig small intestine to in vivo challenge by cholera toxin (CT) was investigated. The small intestine of 14-day-old pigs was more sensitive to CT challenge than that of 14-wk-old animals. In the 14-day jejunum CT-induced fluid secretion was five times that observed in the 14-wk tissue. Similarly, the 14-day ileum produced a fourfold higher secretion than the 14-wk ileum, although the magnitude of ileal secretion was markedly lower than that observed in the jejunum at the same CT dose. This reduced response to CT with age was not due to a reduced secretory capacity of the tissue, since supramaximal doses of prostaglandin E2 and theophylline induced a similar response in tissue from both age groups in vitro. We conclude that these results are consistent with the hypothesis that an antisecretory factor, which naturally inhibits fluid losses in enterotoxigenic diarrhea, is produced in older animals.

Release of Dipeptide Hydrolase Activities from Rat Small Intestine Perfused in Vitro and in Vivo

1979 ◽  
Vol 57 (6) ◽  
pp. 529-534 ◽  
Author(s):  
M. L. G. Gardner ◽  
Jane A. Plumb
Keyword(s):  
Small Intestine ◽  
Physiological Significance ◽  
Peptide Transport ◽  
Rat Small Intestine ◽  
Experimental Procedure ◽  
Specific Process ◽  
Whole Cells ◽  
Anaesthetized Rats

1. Hydrolase activities against three dipeptides were measured in mucosal cytoplasm in unperfused intestines and in mucosal cytoplasm, luminal effluents and serosal secretions after perfusion in vitro and in vivo for 1 h. Intestines in vitro were prepared both from anaesthetized rats and from freshly killed rats. 2. Only 0·6–1·9% of the initial cytoplasmic activity was recovered in the luminal effluent when intestines in vitro were prepared from anaesthetized rats. Recoveries in luminal effluents were similar (1·3–3·3%) during perfusion in vivo. 3. Losses of dipeptidases into the luminal effluent were four to eight times greater when intestines in vitro were prepared from freshly killed animals. 4. Similar losses of dipeptidases into the secretion on to the serosal surface were observed; they too were much greater when intestines were prepared from freshly killed animals. 5. Small losses of mucosal DNA during perfusion were also observed; however, losses of cytoplasmic peptidases were consistently slightly greater. 6. Enzyme loss therefore probably occurs both by sloughing of whole cells and by a more specific process which is greatly influenced by experimental procedure. Caution is necessary in the interpretation of peptide transport experiments in vitro, although the possibility that intraluminal hydrolysis is of physiological significance must not be excluded.

scholarly journals Oral Glutamine Supplementation Benefits Jejunum but Not Ileum

1994 ◽  
Vol 8 (2) ◽  
pp. 108-114
Author(s):  
Paul E Hardy ◽  
Karen L Madsen ◽  
Olin G Thurston ◽  
Stewart M Hamilton ◽  
Ningren Cui ◽  
...  
Keyword(s):  
Small Intestine ◽  
Glutamine Supplementation ◽  
Fluid Absorption ◽  
Protein Ratio ◽  
Injury Model ◽  
Proximal Intestine ◽  
Resection And Anastomosis ◽  
Glutaminase Activity ◽  
Intestinal Absorptive Function

Glutamine is the primary metabolic fuel of the small intestine. The ability of enteral glutamine to support jejunal architecture and metabolism is well established, but its effect on intestinal absorptive function, especially in the terminal ileum, remains undetermined. The purpose of this study was to develop a functional ileal fluid absorption surgical injury model and to determine if oral glutamine supplementation would be beneficial in accelerating healing and restoring function. The effects of either 1 cm resection and ileal end-to-end anastomosis or sham laparotomy on rat in vivo fluid absorption at study start (day 0), one and two days was investigated. In sham-operated rats, fluid absorption was not altered. In contrast, ileal fluid absorption was significantly reduced at days 0 (17.2±4.8 μL/cm/h) and 1 (31.4±13.6 μL/cm/h), but returned to normal by day 2 (71.0±6.2 μL/cm/h) in anastomosed rats. To examine the effects of glutamine in this model, rats were fed either glutamine (2.4 g/kg/day) or an isonitrogenous glycine-supplemented elemental oral diet for five days before their randomization to sham or anastomotic groups. This dose of glutamine reached the ileum and was completely absorbed along the small intestine. Glutamine-fed rats demonstrated no difference in recovery of in vivo ileal fluid absorption, ileal villus morphometric measurements, mg DNA:mg protein ratio, degree of inflammation or glutaminase activity. In contrast, jejunal, but not ileal, villus morphometry, mg DNA:mg protein ratio and glutaminase activity were increased in glutamine-fed ‘not operated’ rats (P<0.01), indicating that the jejunum, but not the ileum, responded to the glutamine-supplemented diet. These studies demonstrate that ileal resection and anastomosis causes transient impairments in in vivo fluid absorption, and oral glutamine supplementation offers a beneficial effect to jejunal, but not ileal, intestinal mucosa. These results suggest that the effects of oral glutamine may be limited to the proximal intestine.

scholarly journals The intestinal-renal axis for arginine synthesis is present and functional in the neonatal pig

2017 ◽  
Vol 313 (2) ◽  
pp. E233-E242 ◽  
Author(s):  
Juan C. Marini ◽  
Umang Agarwal ◽  
Jason L. Robinson ◽  
Yang Yuan ◽  
Inka C. Didelija ◽  
...  
Keyword(s):  
Small Intestine ◽  
Age Groups ◽  
Kidney Tissue ◽  
High Plasma ◽  
Neonatal Pigs ◽  
Plasma Citrulline ◽  
Young Pigs ◽  
Argininosuccinate Synthase ◽  
Neonatal Pig

The intestinal-renal axis for endogenous arginine synthesis is an interorgan process in which citrulline produced in the small intestine is utilized by the kidney for arginine synthesis. The function of this axis in neonates has been questioned because during this period the enzymes needed for arginine synthesis argininosuccinate synthase (ASS1) and lyase (ASL) are present in the gut. However, evidence of high plasma citrulline concentrations in neonates suggests otherwise. We quantified in vivo citrulline production in premature (10 days preterm), neonatal (7 days old), and young pigs (35 days old) using citrulline tracers. Neonatal pigs had higher fluxes (69 µmol·kg−1·h−1, P < 0.001) than premature and young pigs (43 and 45 µmol·kg−1·h−1, respectively). Plasma citrulline concentration was also greater in neonatal pigs than in the other age groups. We also determined the site of synthesis and utilization of citrulline in neonatal and young pigs by measuring organ balances across the gut and the kidney. Citrulline was released from the gut and utilized by the kidney in both neonatal and young pigs. The abundance and localization of the enzymes involved in the synthesis and utilization were determined in intestinal and kidney tissue. Despite the presence of ASS1 and ASL in the neonatal small intestine, the lack of colocalization with the enzymes that produce citrulline results in the release of citrulline by the PDV and its utilization by the kidney to produce arginine. In conclusion, the intestinal-renal axis for arginine synthesis is present in the neonatal pig.

PepT1-mediated fMLP transport induces intestinal inflammation in vivo

2002 ◽  
Vol 283 (6) ◽  
pp. C1795-C1800 ◽  
Author(s):  
Marion Buyse ◽  
Annick Tsocas ◽  
Francine Walker ◽  
Didier Merlin ◽  
Andre Bado
Keyword(s):  
Small Intestine ◽  
Histological Analysis ◽  
Intestinal Inflammation ◽  
In Vitro Study ◽  
Peptide Transporter ◽  
Rat Colon ◽  
Membrane Transporter ◽  
Rat Small Intestine

In the present study, the effect of H+/peptide transporter (PepT1)-mediated N-formylmethionyl-leucyl-phenylalanine (fMLP) transport on inflammation in vivo in the rat small intestine, which expresses high PepT1 levels, and in the rat colon, which does not express PepT1, were investigated using myeloperoxidase (MPO) activity and histological analysis. We found that 10 μM fMLP perfusion in the jejunum for 4 h significantly increased MPO activity and altered the architecture of jejunal villi. In contrast, 10 μM fMLP perfusion in the colon for 4 h did not induce any inflammation. In addition, we have shown that 50 mM Gly-Gly alone did not affect basal MPO activity but completely inhibited the MPO activity induced by 10 μM fMLP in the jejunum. Together, these experiments demonstrate that 1) the differential expression of PepT1 between the small intestine and the colon plays an important role in epithelial-neutrophil interactions and 2) the inhibition of fMLP uptake by jejunal epithelial cells (expressing PepT1) reduces the neutrophil ability to move across the epithelium, in agreement with our previously published in vitro study. This report constitutes the first in vivo study showing the implication of a membrane transporter (PepT1) in intestinal inflammation.

Electrogenic, proton-coupled, intestinal dipeptide transport in herbivorous and carnivorous teleosts

1996 ◽  
Vol 270 (5) ◽  
pp. R939-R947 ◽  
Author(s):  
M. Thamotharan ◽  
J. Gomme ◽  
V. Zonno ◽  
M. Maffia ◽  
C. Storelli ◽  
...  
Keyword(s):  
Specific Inhibitor ◽  
Intestinal Transport ◽  
Membrane Vesicles ◽  
Proton Gradient ◽  
Peptide Transport ◽  
Transport Systems ◽  
Peptide Transporter ◽  
Carrier System ◽  
Carrier Mediated Transport ◽  
Dipeptide Transport

In both herbivorous tilapia (Oreochromis mossambicus) and carnivorous rockfish (Sebastes caurinus) intestinal and pyloric cecal brush-border membrane vesicles (BBMV), [14C]glycylsarcosine ([14C]Gly-Sar) uptake was stimulated by a transmembrane proton gradient. A transmembrane K(+)-diffusion potential (inside negative) stimulated [14C]Gly-Sar uptake above that observed with short-circuited vesicles, whereas an inwardly directed Na+ gradient in both fishes had no effect on peptide uptake. In tilapia, [14C]Gly-Sar influx occurred by the combination of 1) a high-affinity, saturable, proton gradient-dependent carrier system [Kt [concentration that equals one-half of maximum influx (Jmax)] = 0.56 +/- 0.08 mM; Jmax = 1,945.0 +/- 174.6 pmol.mg protein-1.10 s-1]; 2) a low-affinity, nonsaturable (within 1-10 mM), proton gradient-dependent carrier system (nonsaturable carrier-mediated transport component = 4,514.0 +/- 28.1 pmol.mg protein-1.10 s-1.mM-1); and 3) a diffusional component accounting for < 10% of total influx within the concentration range tested. Influx (10 s) of 1-10 mM [14C]Gly-Sar in tilapia intestine was significantly (P < 0.01) inhibited by 10 mM diethylpyrocarbonate, a specific inhibitor of proton-coupled peptide transport systems. [14C]Gly-Sar influx into tilapia BBMV showed cis-inhibition and trans-stimulation by Gly-Pro, suggesting that [14C]Gly-Sar and Gly-Pro shared the same mucosal peptide transporter in fish. These observations strongly suggest that intestinal transport of peptides in herbivorous and carnivorous fishes is proton gradient dependent, electrogenic, sodium independent, and qualitatively resembles the peptide transport paradigm proposed for mammals.

Effect of Lipopolysaccharide on Peptide Transporter 1 Expression in Rat Small Intestine and Its Attenuation by Dexamethasone

Digestion ◽  
2002 ◽  
Vol 65 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Hong-Jin Shu ◽  
Hiroaki Takeda ◽  
Haruhide Shinzawa ◽  
Tsuneo Takahashi ◽  
Sumio Kawata
Keyword(s):  
Small Intestine ◽  
Peptide Transporter ◽  
Rat Small Intestine ◽  
Peptide Transporter 1

Inhibition of Fibrinolytic Activity In-Vivo by Dexamethasone Is Counterbalanced by an Inhibition of Platelet Aggregation

1992 ◽  
Vol 68 (01) ◽  
pp. 069-073 ◽  
Author(s):  
J J J van Giezen ◽  
J W C M Jansen
Keyword(s):  
Platelet Aggregation ◽  
Fibrinolytic Activity ◽  
Ex Vivo ◽  
Dose Range ◽  
Coagulation System ◽  
Loop Model ◽  
Prothrombotic State ◽  
Inhibition Of Platelet Aggregation ◽  
Pai 1

SummaryDexamethasone decreases the fibrinolytic activity in cultured medium of several cell types by an induction of PAI-1 synthesis. As a result of this enhanced PAI-1 synthesis a prothrombotic state is expected in patients treated with dexamethasone. However, such a prothrombotic state is not reported as a major adverse effect. We have studied the effects of dexamethasone (dose range: 0.1–3.0 mg/kg) on the fibrinolytic system of rats after a 5 day pretreatment period. It appeared that dexamethasone dose dependently decreased the fibrinolytic activity (a dose of 1 mg/kg showed a reduction of about 40%). This reduced fibrinolytic activity could be functionally translated into an increased thrombus size as measured with a venous thrombosis model: thrombus size was increased by 50% with 1 mg/kg dexamethasone. No effects could be measured on the coagulation system, but it appeared that ex-vivo measured platelet aggregation was dose dependently inhibited by dexamethasone treatment. This effect resulted in-vivo in prolonged obstruction times as measured with a modified aorta-loop model. These results indicate that the expected prothrombotic state due to a diminished fibrinolytic activity caused by dexamethasone is counterbalanced by an inhibition of platelet aggregation.

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