Glucose and glutamine provide similar proportions of energy to mucosal cells of rat small intestine

1997 ◽  
Vol 273 (4) ◽  
pp. G968-G978 ◽  
Author(s):  
Sharon E. Fleming ◽  
Kirsten L. Zambell ◽  
Mark D. Fitch
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Metabolic Pathways ◽  
Glycolytic Flux ◽  
Net Energy ◽  
Intestinal Epithelial ◽  
Atp Production ◽  
Distal Small Intestine ◽  
Mucosal Cells ◽  
In Cells

The objectives of this study were to establish a reliable method for quantifying glycolytic flux in intestinal epithelial cells, to determine the proportion of energy provided to small intestine epithelial cells by glucose vs. glutamine, and to determine whether there was an energetic advantage to having both substrates present simultaneously. There was substantial retention of 3H in alanine and lactate when [2-3H]glucose was used as tracer for quantifying glycolysis, and the magnitude of the3H retention was influenced by the presence of other substrates and metabolites. Detritiation was at least 99% complete, however, when [3-3H]glucose was used as tracer in this system and the tritium was recovered as3H2O. Glycolytic flux was six- to sevenfold higher in cells of the proximal than distal small intestine but was not significantly different for young adult (4 mo) vs. aged adult (24 mo) rats. Net ATP production from exogenous substrates was higher when both glucose and glutamine were present simultaneously than when either substrate was present alone, and glucose was calculated to provide 50–60% of the net ATP produced from these two substrates. Most of the energy produced from glucose was produced via the anaerobic metabolic pathways (78% for glucose alone, 95% with glucose and glutamine). Net energy production was calculated to be 10% lower in cells from aged animals than in those from young animals, since CO2 production from these major substrates was lower in cells from aged animals.

Oxidation of glucose carbon entering the TCA cycle is reduced by glutamine in small intestine epithelial cells

1995 ◽  
Vol 268 (6) ◽  
pp. G879-G888 ◽  
Author(s):  
C. E. Kight ◽  
S. E. Fleming
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Glucose Oxidation ◽  
Tca Cycle ◽  
Proximal Segment ◽  
Distal Small Intestine ◽  
Glucose Carbon ◽  
The Tca Cycle ◽  
Oxidation Of Glucose ◽  
In Cells

The influence of glutamine on glucose oxidation was assessed in epithelial cells isolated from the mucosa of the proximal, mid-, and distal small intestine of young, fed, male rats. Glucose oxidation declined along the length of the small intestine, with values from the mid- and distal segments representing approximately 55% and 40%, respectively, of the value from the proximal segment. A gradient along the small intestine was noted also in the influence of glutamine on glucose oxidation: glutamine suppressed glucose oxidation approximately 60% in the proximal small intestine, 39% in the mid-intestine, and 31% in the distal small intestine. Glutamine suppressed the oxidation of glucose carbon that entered the tricarboxylic acid (TCA) cycle; this was determined using CO2 ratios derived from acetate and glucose isotopes. In cells from the proximal segment, the probability that carbon entering the cycle would complete one full turn was reduced by glutamine from 0.77 to 0.28. The entry of glucose-derived pyruvate into the TCA cycle did not appear to be influenced by the presence of glutamine, however. Glutamine had no influence on the proportion of glucose metabolism that occurred via the pentose phosphate pathway (which averaged 5% or less), but reduced flux of carbon through pyruvate carboxylase relative to flux through pyruvate dehydrogenase from 40% to 9% in cells from the proximal segment. These data suggest that, in the presence of glutamine, the fate of pyruvate carbon (derived from glucose or elsewhere) entering the TCA cycle is altered from that of oxidation to anaplerosis and subsequent efflux of TCA cycle intermediates into newly synthesized compounds.

The protease phenotype and crystalline nature of the granules of intraepithelial mast cells in Trichinella spiralis-infected mice

1995 ◽  
Vol 53 ◽  
pp. 818-819
Author(s):  
D.S. Friend ◽  
N. Ghildyal ◽  
M.F. Gurish ◽  
K.F. Austen ◽  
R.L. Stevens
Keyword(s):  
Small Intestine ◽  
Mast Cells ◽  
Epithelial Cells ◽  
Lamina Propria ◽  
Trichinella Spiralis ◽  
Intestinal Epithelial ◽  
Carboxypeptidase A ◽  
C3h Mice ◽  
Granule Morphology ◽  
Crystalline Nature

Trichinella spiralis induces a profound mastocytosis and eosinophilia in the small intestine of the infected mouse. Mouse mast cells (MC) store in their granules various combinations of at least five chymotryptic chymases [designated mouse MC protease (mMCP) 1 to 5], two tryptic proteases designated mMCP-6 and mMCP-7 and an exopeptidase, carboxypeptidase A (mMC-CPA). Using antipeptide, protease -specific antibodies to these MC granule proteases, immunohistochemistry was done to determine the distribution, number and protease phenotype of the MCs in the small intestine and spleen 10 to >60 days after Trichinella infection of BALB/c and C3H mice. TEM was performed to evaluate the granule morphology of the MCs between intestinal epithelial cells and in the lamina propria (mucosal MCs) and in the submucosa, muscle and serosa of the intestine (submucosal MCs).As noted in the table below, the number of submucosal MCs remained constant throughout the study. In contrast, on day 14, the number of MCs in the mucosa increased ~25 fold. Increased numbers of MCs were observed between epithelial cells in the mucosal crypts, in the lamina propria and to a lesser extent, between epithelial cells of the intestinal villi.

Effect of leptin on intestinal apolipoprotein AIV in response to lipid feeding

2001 ◽  
Vol 281 (3) ◽  
pp. R753-R759 ◽  
Author(s):  
Takashi Doi ◽  
Min Liu ◽  
Randy J. Seeley ◽  
Stephen C. Woods ◽  
Patrick Tso
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Regional Distribution ◽  
Intestinal Epithelial ◽  
Lipid Infusion ◽  
Intraduodenal Infusion ◽  
Crypt Cells

We determined apolipoprotein AIV (apo AIV) content in intestinal epithelial cells using immunohistochemistry when leptin was administered intravenously. Most of the apo AIV immunoreactivity in the untreated intestine was located in the villous cells as opposed to the crypt cells. Regional distribution of apo AIV immunostaining revealed low apo AIV content in the duodenum and high content in the jejunum that gradually decreases caudally toward the ileum. Intraduodenal infusion of lipid (4 h) significantly increased apo AIV immunoreactivity in the jejunum and ileum. Simultaneous intravenous leptin infusion plus duodenal lipid infusion markedly suppressed apo AIV immunoreactivity. Duodenal lipid infusion increased plasma apo AIV significantly (measured by ELISA), whereas simultaneous leptin infusion attenuated the increase. These findings suggest that leptin may regulate circulating apo AIV by suppressing apo AIV synthesis in the small intestine.

scholarly journals Ultrastructural Changes in the Small Intestine of Neonatal Calves with Enteric Colibacillosis

1982 ◽  
Vol 19 (2) ◽  
pp. 190-201 ◽  
Author(s):  
G. R. Pearson ◽  
E. F. Logan
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Small Groups ◽  
Ultrastructural Changes ◽  
Post Inoculation ◽  
Cytoplasmic Inclusions ◽  
Distal Small Intestine ◽  
Enteropathogenic Strain ◽  
Neonatal Calves ◽  
Small Intestines

The small intestines of calves inoculated orally with the enteropathogenic strain of Escherichia coli 0101:K'B41′, K99 were examined by electron microscopy at 3, 6, 12, 16, 21, 36, 69, 70 and 72 hours after inoculation. The challenge organism adhered to the mucosa of the distal small intestine from six hours post-inoculation. Bacteria were separated from the microvillous brush border by a gap of 200 to 300 nm in which bacterial fimbriae and the microvillous glycocalyx were seen. Bacteria never were found in epithelial cells but were present in macrophages in the lamina propria from 12 hours. At three and six hours, cytopathic changes were not seen in the small intestine, but from 12 hours epithelial cells on affected villi had blunt and thick microvilli and contained cytoplasmic inclusions. Epithelial cells were seen frequently in the process of extrusion from the villi, either singly, in small groups, or as ribbons of cells. Intervillous bridges, characteristic of villous fusion, were seen frequently from 69 hours.

High affinity L-aspartate transport in chick small intestine

1987 ◽  
Vol 252 (1) ◽  
pp. C105-C114 ◽  
Author(s):  
T. G. Wingrove ◽  
G. A. Kimmich
Keyword(s):  
Small Intestine ◽  
Membrane Potential ◽  
Epithelial Cells ◽  
Intracellular Ph ◽  
Transport Function ◽  
Flux Enhancement ◽  
High Affinity ◽  
Absolute Requirement ◽  
Potential Sensitivity ◽  
In Cells

Epithelial cells isolated from chick small intestine were used to study the mechanism of L-aspartate transport. Two kinetically distinct uptake systems of high (Km' = 16 microM) and low (Km'' = 2.7 mM) affinity are observed. This paper examines the cation dependence and membrane potential sensitivity of the high affinity system. Unidirectional influx studies indicate that extracellular Na+ is an absolute requirement for transport function. Flux is optimal when K+ is present intracellularly, however this cation is not required for Na+-dependent L-aspartate uptake. In the absence of K+, flux enhancement is observed when the intracellular pH is acidic. In contrast, acidic intracellular pH is inhibitory in cells that are preequilibrated with K+. Sodium ([Na+]o greater than [Na+]i gradients, and potassium ([K+]o less than [K+]i) or proton ([H+]o less than [H+]i) gradients can independently energize the Na+-dependent accumulation of L-aspartate above equilibrium levels, suggesting that Na+ and L-aspartate cotransport occurs with concomitant K+ or H+ antiport. L-Aspartate influx is insensitive to membrane potential changes created by inwardly directed anion gradients in the presence or absence of intracellular K+. A model is presented that is consistent with electroneutral Na+-coupled transfer with an ion antiport site of low specificity.

Nitric oxide regulates energy metabolism and Bcl-2 expression in intestinal epithelial cells

1998 ◽  
Vol 274 (5) ◽  
pp. G797-G801 ◽  
Author(s):  
Manabu Nishikawa ◽  
Kenta Takeda ◽  
Eisuke F. Sato ◽  
Tetso Kuroki ◽  
Masayasu Inoue
Keyword(s):  
Nitric Oxide ◽  
Epithelial Cells ◽  
Prolonged Exposure ◽  
Intestinal Epithelial Cells ◽  
Enteric Bacteria ◽  
Intestinal Lumen ◽  
Intestinal Epithelial ◽  
Mucosal Cells ◽  
Respiration Of Mitochondria ◽  
Induced Changes

Nitric oxide (NO) inhibits the respiration of mitochondria and enteric bacteria, particularly under low O2concentration, and induces apoptosis of various types of cells. To gain insight into the molecular role of NO in the intestine, we examined its effects on the respiration, Ca2+status, and expression of Bcl-2 in cultured intestinal epithelial cells (IEC-6). NO reversibly inhibited the respiration of IEC-6 cells, especially under physiologically low O2concentration. Although NO elevated cytosolic Ca2+as determined by the fura 2 method, the cells were fairly resistant to NO. Kinetic analysis revealed that prolonged exposure to NO elevated the levels of Bcl-2 and suppressed the NO-induced changes in Ca2+status of the cells. Because Bcl-2 possesses antiapoptotic function, toxic NO effects might appear minimally in enterocytes enriched with Bcl-2. Thus NO might effectively exhibit its antibacterial action in anaerobic intestinal lumen without inducing apoptosis of Bcl-2-enriched mucosal cells.

scholarly journals DES2 protein is responsible for phytoceramide biosynthesis in the mouse small intestine

2004 ◽  
Vol 379 (3) ◽  
pp. 687-695 ◽  
Author(s):  
Fumio OMAE ◽  
Masao MIYAZAKI ◽  
Ayako ENOMOTO ◽  
Minoru SUZUKI ◽  
Yusuke SUZUKI ◽  
...  
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Intestinal Epithelial ◽  
Vitro Assay ◽  
Peptide Antibody ◽  
Mouse Small Intestine ◽  
Mrna Content ◽  
Crypt Cells

The C-4 hydroxylation of sphinganine and dihydroceramide is a rate-limiting reaction in the biosynthesis of phytosphingolipids. Mouse DES1 (MDES1) cDNA homologous to the Drosophila melanogaster degenerative spermatocyte gene-1 (des-1) cDNA leads to sphingosine Δ4-desaturase activity, and another mouse homologue, MDES2, has bifunctional activity, producing C-4 hydroxysphinganine and Δ4-sphingenine in yeast [Ternes, Franke, Zahringer, Sperling and Heinz (2002) J. Biol. Chem. 277, 25512–25518]. Here, we report the characterization of mouse DES2 (MDES2) using an in vitro assay with a homogenate of COS-7 cells transfected with MDES2 cDNA and N-octanoyl-sphinganine and sphinganine as substrates. MDES2 protein prefers dihydroceramide as a substrate to sphinganine, and exhibits dihydroceramide Δ4-desaturase and C-4 hydroxylase activities. MDES2 mRNA content was high in the small intestine and abundant in the kidney. In situ hybridization detected signals of MDES2 mRNA in the crypt cells. Immunohistochemistry using an anti-MDES2 peptide antibody stained the crypt cells and the adjacent epithelial cells. These results suggest that MDES2 is the dihydroceramide C-4 hydroxylase responsible for the biosynthesis of enriched phytosphingoglycolipids in the microvillous membranes of intestinal epithelial cells.

scholarly journals Intectin, a Novel Small Intestine-specific Glycosylphosphatidylinositol-anchored Protein, Accelerates Apoptosis of Intestinal Epithelial Cells

2004 ◽  
Vol 279 (41) ◽  
pp. 42867-42874 ◽  
Author(s):  
Hidefumi Kitazawa ◽  
Tamao Nishihara ◽  
Tadahiro Nambu ◽  
Hitoshi Nishizawa ◽  
Masanori Iwaki ◽  
...  
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial

scholarly journals Role of Intestinal Epithelial Cells in Immune Effects Mediated by Gram-Positive Probiotic Bacteria: Involvement of Toll-Like Receptors

2005 ◽  
Vol 12 (9) ◽  
pp. 1075-1084 ◽  
Author(s):  
Gabriel Vinderola ◽  
Chantal Matar ◽  
Gabriela Perdigon
Keyword(s):  
Small Intestine ◽  
B Cells ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Primary Cultures ◽  
Clonal Expansion ◽  
Probiotic Bacteria ◽  
Intestinal Epithelial ◽  
Toll Like Receptors

ABSTRACT The mechanisms by which probiotic bacteria exert their effects on the immune system are not completely understood, but the epithelium may be a crucial player in the orchestration of the effects induced. In a previous work, we observed that some orally administered strains of lactic acid bacteria (LAB) increased the number of immunoglobulin A (IgA)-producing cells in the small intestine without a concomitant increase in the CD4+ T-cell population, indicating that some LAB strains induce clonal expansion only of B cells triggered to produce IgA. The present work aimed to study the cytokines induced by the interaction of probiotic LAB with murine intestinal epithelial cells (IEC) in healthy animals. We focused our investigation mainly on the secretion of interleukin 6 (IL-6) necessary for the clonal expansion of B cells previously observed with probiotic bacteria. The role of Toll-like receptors (TLRs) in such interaction was also addressed. The cytokines released by primary cultures of IEC in animals fed with Lactobacillus casei CRL 431 or Lactobacillus helveticus R389 were determined. Cytokines were also determined in the supernatants of primary cultures of IEC of unfed animals challenged with different concentrations of viable or nonviable lactobacilli and Escherichia coli, previously blocked or not with anti-TLR2 and anti-TLR4. We concluded that the small intestine is the place where a major distinction would occur between probiotic LAB and pathogens. This distinction comprises the type of cytokines released and the magnitude of the response, cutting across the line that separates IL-6 necessary for B-cell differentiation, which was the case with probiotic lactobacilli, from inflammatory levels of IL-6 for pathogens.

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