scholarly journals Glucose metabolism in the mucosa of the small intestine. Changes of hexokinase activity during perfusion of the proximal half of rat small intestine

1970 ◽  
Vol 116 (1) ◽  
pp. 43-48 ◽  
Author(s):  
R. J. Mayer ◽  
P. Shakespeare ◽  
G. Hübscher
Keyword(s):  
Small Intestine ◽  
Lactate Dehydrogenase ◽  
Particulate Fraction ◽  
Original Activity ◽  
Hexokinase Activity ◽  
Soluble Cell ◽  
Proximal Half ◽  
Total Particulate Fraction

1. The effect of perfusion on the activities of hexokinase and lactate dehydrogenase was studied in the proximal half of the small intestine of fed and starved rats. 2. Perfusion of preparations from starved rats with a medium containing glucose caused a significant increase in hexokinase activity of the particle-free supernatant. The increase in activity was observed as early as 5min after the start of perfusion and persisted for up to 66min of perfusion. No increase in hexokinase activity of the particle-free supernatant was observed when a medium containing mannitol was used. As a further control, preparations from fed rats were perfused under the same conditions. With the medium containing glucose, the hexokinase activity of the particle-free supernatant remained unchanged during the first 15min of perfusion and thereafter fell gradually until, after 66min of perfusion, 73% of the original activity was retained. 3. The activity of lactate dehydrogenase in the particle-free supernatant prepared from the proximal half of the untreated small intestine of starved rats was significantly lower than in corresponding preparations from fed animals. However, it did not change significantly on perfusion with media containing either mannitol or glucose. 4. The distribution of hexokinase activity between total particulate fraction and particle-free supernatant was measured in preparations from starved rats after perfusion for 5–10min. In preparations that had not been perfused the ratio of hexokinase activity in total particulate fraction/particle-free supernatant was significantly higher in starved than in fed animals. After perfusion with a medium containing glucose, the total homogenate activity had not changed significantly, whereas the ratio of hexokinase activity in total particulate fraction/particle-free supernatant decreased significantly and approached the value obtained with fed animals. 5. The results agree with the view that the glucose-dependent increase of hexokinase activity in the soluble cell compartment as observed in vivo and in vitro in the intestinal mucosa of starved rats is brought about by a release of hexokinase activity from a particulate subcellular structure(s).

scholarly journals Glucose metabolism in the mucosa of the small intestine. The effect of glucose on hexokinase activity

1969 ◽  
Vol 111 (1) ◽  
pp. 63-67 ◽  
Author(s):  
P. Shakespeare ◽  
L M Srivastava ◽  
G. Hübscher
Keyword(s):  
Small Intestine ◽  
Similar Amount ◽  
Long Chain Fatty Acids ◽  
Stomach Tube ◽  
Hexokinase Activity ◽  
Dietary Components ◽  
Effect Of Glucose ◽  
Long Chain

1. The effect of three dietary components on hexokinase activity in the mucosa of rat small intestine was studied in vivo. Glucose, amino acids or an emulsion of monoglyceride with long-chain fatty acids were given by stomach tube to previously starved rats, and hexokinase activity was determined in the particle-free supernatant of mucosal homogenates. The formation of lactate from glucose and glucose 6-phosphate respectively was also measured. 2. When the three dietary components were given in isocaloric amounts, only glucose brought about an increase in hexokinase activity. 3. Intravenous injection of a similar amount of glucose to that given orally did not alter hexokinase activity. 4. An increase in the hexokinase activity of the particle-free supernatant prepared from mucosal homogenates was also observed after sacs of the small intestine of starved rats had been incubated in vitro in a medium containing glucose. Hexokinase activity increased to the values observed in corresponding preparations from fed rats, and this increase was strictly glucose-dependent.

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

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.

scholarly journals Absorption of lactulose from mammalian gastrointestinal tract

1979 ◽  
Vol 41 (1) ◽  
pp. 47-51 ◽  
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.

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

Animals ◽  
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.

In vivo and in vitro Absorption of Amino Acids and Dipeptides in the Small Intestine of Uremic Rats

Nephron ◽  
1982 ◽  
Vol 31 (3) ◽  
pp. 273-276 ◽  
Author(s):  
G. Sterner ◽  
T. Lindberg ◽  
T. Denneberg
Keyword(s):  
Amino Acids ◽  
Small Intestine

scholarly journals Measurement of rapidly available glucose (RAG) in plant foods: a potential in vitro predictor of the glycaemic response

1996 ◽  
Vol 75 (3) ◽  
pp. 327-337 ◽  
Author(s):  
Hans N Englyst ◽  
Jan Veenstra ◽  
Geoffrey J Hudson
Keyword(s):  
Small Intestine ◽  
Direct Calculation ◽  
Simple Calculation ◽  
Glycaemic Index ◽  
Equal Weight ◽  
Glycaemic Response ◽  
Human Small Intestine ◽  
Reference Amount

AbstractThe glycaemic index (GI) is an in vivo measurement based on the glycaemicresponse to carbohydrate-containing foods, and allows foods to be ranked on the basis of the rate of digestion and absorption of the carbohydrates that they contain. GI values are normalizedto a reference amount of available carbohydrate and do not reflect the amounts of carbohydrate normally present in foods; for example, a food with a low content of carbohydrates will have a high GI value if that carbohydrate is digested and absorbed rapidly in the human small intestine. This is potentially confusing for a person wishing to control his or her blood glucoselevels by the choice of foods. The rate and extent of starch digestion in vitro has been measured using a technique that classifies starch into three major fractions: rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS). In addition, thistechnique gives a value for rapidly available glucose (RAG), which includes RDS, free glucose and the glucose moiety of sucrose. When the values for thirty-nine foods were expressed on the basis ofthe available carbohydrate content of these foods, highly significant (P<0·001) positive correlations were observed between GI and both RDS and RAG. The measurement of RAGin vitro provides values for direct calculation of the amount of glucose likely to be rapidly absorbed in the human small intestine and,thus, to influence blood glucose and insulin levels. These values can be used to compare foods, as eaten,on an equal-weight basis. Food-table RAG values would allow simple calculation of the total amount of RAG provided by single foods, by whole meals and by whole diets. Studies are planned in which RAG and the glycaemic response in man will be measured for identical food products.

Isolation of hydroxytyrosol from olive leaves extract, radioiodination and investigation of bioaffinity using in vivo/in vitro methods

2013 ◽  
Vol 101 (9) ◽  
pp. 585-593 ◽  
Author(s):  
M. Ozkan ◽  
F. Z. Biber Muftuler ◽  
A. Yurt Kilcar ◽  
E. I. Medine ◽  
P. Unak
Keyword(s):  
Small Intestine ◽  
Phenolic Compounds ◽  
Biological Activities ◽  
In Vivo Studies ◽  
Flavonoid Content ◽  
Olive Leaves ◽  
In Vitro Methods ◽  
Extraction And Purification

Summary It is known that medicinal plants like olive have biological activities due to their flavonoid content such as olueropein, tyrosol, hydroxytyrosol etc. In current study, hydroxytrosol (HT) which is one of the major phenolic compounds in olive, olive leaves and olive oil, was isolated after methanol extraction and purification of olive leaves which are grown in the northern Anatolia region of Turkey. The isolated HT was radiolabeled with 131I (131I-HT) and the bioaffinity of this radiolabeled component of olive leaves extract was investigated by using in vivo/in vitro methods. It was found that HT could be radiolabeled with 131I in yields of 95.6±4.4% (n = 8), and in vivo studies showed that 131I-HT is taken up by urinary bladder, stomach, small intestine, large intestine, breast and prostate. Significant incorporation of activity was observed in cell lines via in vitro studies.

Bulk isolation of renal PCT and PST. II. Differential responses to anoxia or hypoxia

1990 ◽  
Vol 259 (1) ◽  
pp. F176-F185 ◽  
Author(s):  
C. E. Ruegg ◽  
L. J. Mandel
Keyword(s):  
Lactate Dehydrogenase ◽  
O2 Consumption ◽  
Atp Content ◽  
Hypoxic Injury ◽  
Biochemical Responses ◽  
In Vitro Exposure ◽  
Differential Responses

Innate biochemical responses of rabbit renal proximal convoluted (PCT) and straight (PST) segments following in vitro exposure to anoxia or hypoxia were investigated to delineate the mechanisms responsible for segment-selective injury in vivo. After bulk isolation, suspensions (1 mg/ml) enriched in either PCT or PST were preincubated in Dulbecco's modified Eagle's-Ham's F-12 medium for 1 h before being exposed to either 40 min of anoxia (N2) or 120 min of hypoxia (1% O2) and 1 h of recovery under air-CO2 conditions. After recovery from anoxia, the percent of control values for each viability indicator in PCT and PST, respectively, were as follows: O2 consumption (QO2), 30/50; ATP content, 22/49; K+ content, 60/70; and percent lactate dehydrogenase (LDH) release, 66/45. Likewise, following recovery from hypoxia, the percent of control values for PCT and PST, respectively, were as follows: QO2, 50/90; ATP, 16/57; K+, 52/79; LDH, 45/17. These differential responses indicate that PCT segments were innately more susceptible to anoxic and hypoxic injury than PST segments. Because ATP content was significantly higher in PST segments immediately after anoxia and hypoxia, we investigated glucose-dependent responses during anoxia by exposing these segments to 30 min of anoxia in nutrient buffer with or without glucose. Results from these experiments demonstrate that the PST protection from anoxia was glucose dependent because removal of glucose from the nutrient buffers during anoxia abolishes the differential responses between PCT and PST. The in vitro PCT sensitivity observed here contrasts with the PST sensitivity observed following in vivo ischemia, suggesting that hemodynamic factors present in vivo may ultimately determine the overall susceptibility of PST segments in situ.

Uptake and compartmental distribution of fatty acid by rat small intestine in vivo

1975 ◽  
Vol 228 (5) ◽  
pp. 1409-1414
Author(s):  
S Mishkin ◽  
M Yalovsky ◽  
JI Kessler
Keyword(s):  
Fatty Acids ◽  
Small Intestine ◽  
Fatty Acid ◽  
Entire Length ◽  
Rat Small Intestine ◽  
Pass Through

The uptake and esterification of micellar [3-H]oleate and [14-C] palmitate were uniform along the entire length of the small intestine in vivo. Fatty acids (FA) radioactivity taken up by the small intestine could be described in terms of four functionally distinct compartments analogous to those described in vitro. The KRP-extractable compartment (KEC) and albumin-extractable compartment (AEC) contained reversibly adherent unesterified FA radioactivity, while the tissue free and esterified FA compartments contained irreversibly bound radioactivity. Wheras 27% and 63% of FA uptake were reversibly bound in the KEC and AEC by the most proximal and most distal regions of the small intestine in vitro (15), less than 10% was contained in these compartments in vivo, independent of location. Linear inverse relationships were found betweeen tissue FA esterification and proportion of FA radioactivity present in the KEC,AEC, and the tissue free FA compartment in vivo. These observations allow for the possibility that FA molecules pass through these compartments prior to esterification.

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