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PubMed1995

[Influence of intake of vegetable oils on the in vitro intestinal absorption of glucose in golden hamsters].

Male Hamsters (Mesocricetus aureatus) were fed standardized diets with 15% Rose hip, Sunflower, Olive or Coconut oil for four weeks, in order to determine the influence of vegetable oils with different degree of unsaturation over the intestinal absorption of glucose. The concentration of glucose in the serosal solution at 20, 40 and 60 minutes, was quantified in pieces of everted intestine of each animal, after the feeding period was over. A lower concentration of glucose was observed in the Olive group, although it was statistically significant only when compared to the Rose hip and Coconut oil group (P < 0.05). The groups fed Rose hip and Coconut showed a similar pattern, even though they are oils with extreme and opposing degree of unsaturation. We explain this by the triggering of homeostatic mechanisms in the cellular membranes of the enterocytes when faced to a nutritional stress caused by the saturated and unsaturated fatty acids of those oils. We can conclude that the in vitro intestinal absorption of glucose in golden hamster is modified by dietary lipids. The lower absorption of glucose seen in the Olive group could be caused a specific action of a fatty acid or of its degree of unsaturation.

Animals↗
PubMed1986

Influence of bile salts and lipids on intestinal absorption of griseofulvin in man.

The influence of bile salts and lipids on the intestinal absorption of griseofulvin has been studied in 11 healthy male volunteers by the intestinal perfusion technique. The drug in a nutrient solution (Realmentyl) was perfused into the second part of duodenum at 5 ml/min. Intestinal samples were taken continuously at 1 ml/min, 20 cm (at the angle of Treitz) and 45 cm distal to the perfusion point. To study the effect of lipids on griseofulvin absorption, the drug was perfused with solutions A and B, of which B contained a total lipid and caloric load three times that of A. The influence of bile salts on griseofulvin absorption was examined by perfusing the drug on Day 1 with bile salts and again on the following day after bile salt depletion. Bile salts and a varying quantity of lipid perfusate had no significant influence on the duodeno-jejunal griseofulvin absorption rate per cm of intestine. Lipids, however, may still play a role in griseofulvin absorption along the entire intestine.

Adult↗
PubMed1981

Intestinal absorption of D-glucose, D-galactose and L-leucine in male growing rats fed a raw field bean (Vicia faba L.) diet.

Male growing rats were fed diets containing either raw field bean (Vicia faba L.) or casein as the only source of protein. Diets were fed ad libitum for 5 weeks. Body weight gain was significantly impaired, and rates of both in vivo and in vitro intestinal absorption of D-glucose, D-galactose and L-leucine were reduced, in rats fed the legume diet. The addition of methionine to the bean diet did not alter either growth or intestinal absorption rates. No significant differences in intestinal oxygen uptake were found between the treatment groups. It is suggested that the antinutritive substances contained in the raw legume Vicia faba are responsible for the inhibitory effects observed in this experiment.

Animal Feed↗
PubMedDate not supplied

Lack of correlation between jejunal mucosal morphology and intestinal absorption in the hepatosplenic form of schistosomiasis mansoni.

Eleven patients with the hepatosplenic form of schistosomiasis mansoni were studied. Intestinal absorption of fat and xylose was normal in all patients. Despite these normal absorption parameters, the mucosa showed variable degrees of villus atrophy and an increase of the number of inflammatory cells in the lamina propria. Through morphometric analysis it was seen that the villi were shorter and the ratio villus height/crypt depth was increased in schistosomiasis patients as compared to normal control children. Five of the 11 biopsies contained granulomata with ova in the mucosa or submucosa.

Adolescent↗
PubMed1991

A kinetic study of some factors which influence the intestinal absorption of calcium in rats.

Rats weighing 100 +/- 8 g were used in an in vivo kinetic study of the intestinal absorption of calcium (CaA) from three systems: 1) CaCl2, 2) whole cow's milk (M), and 3) a staple Brazilian diet (SBD). Food substrates were treated with HCl, neutralized and diluted with 0.15 mM NaCl to different concentrations. Each dilution was assayed by introducing 2 ml into the small intestine and the final amount of Ca2+ in the small intestine was determined 30 min later. The values for velocity (v = Vmax (Ca2+)/(Ca2+) + Km) and affinity (1/Km) for the food substrates were 1.35, 15.51 and 2.31 micrograms Ca2+/min and 0.29, 0.016 and 0.266 micrograms Ca2+/ml, respectively. We conclude that the higher affinities observed for CaCl2 and SBD were not correlated with velocity. Factors modifying CaA appear to be protein (stimulator) and phytate and fiber (inhibitors).

Animals↗
PubMed1985

Effect of leucine on intestinal absorption of tryptophan in rats.

1. To elucidate the causal relation between leucine and the lowering of hepatic NAD content of rats fed on a leucine-excessive diet (Yamada et al. 1979), the effect of leucine on intestinal absorption of tryptophan was investigated. 2. Co-administration of [3H]tryptophan and leucine, with leucine at ten times the level of tryptophan, delayed absorption of L-[side chain 2,3-3H]tryptophan from the digestive tract and incorporation of [3H]tryptophan into portal blood, the liver and a protein fraction of the liver. After 120 min, more than 95% of tryptophan was absorbed whether [3H]tryptophan was administered with or without leucine. 3. Co-administration of a mixture of ten essential amino acids, in proportions simulating casein, with [3H]tryptophan markedly delayed absorption of tryptophan from the digestive tract. The addition of supplementary leucine to the amino acid mixture, however, caused no further delay. 4. In rats prefed a leucine-excessive diet for 1 week [3H]tryptophan was absorbed at the same rate as in rats fed on a control diet. 5. The results indicate that competition between tryptophan and leucine for intestinal absorption did not cause lowering of hepatic NAD.

Amino Acids, Essential↗
PubMed1996

Mucoadhesive polymers in peroral peptide drug delivery. VI. Carbomer and chitosan improve the intestinal absorption of the peptide drug buserelin in vivo.

PURPOSE: To evaluate the effect of the crosslinked poly(acrylate) carbomer 934P (C934P) and its freeze-dried neutralized sodium salt (FNaC934P) as well as chitosan hydrochloride on the intestinal absorption of the peptide drug buserelin. METHODS: Buserelin was applied intraduodenally in control buffer, 0.5% (w/v) C934P, 0.5% (w/v) FNaC934P, 1.5% (w/v) chitosan hydrochloride or FNaC934P/chitosan hydrochloride (1:1 (v/v)) mixture in rats. RESULTS: All polymer preparation showed a statistically significant improvement of buserelin absorption compared to the control solution. The absolute bioavailabilities for the different polymer preparations were: control, 0.1%; 0.5% FNaC934P, 0.6%; 0.5% C934P, 2.0%; chitosan hydrochloride, 5.1% and FNaC934P/chitosan hydrochloride (1:1 (v/v)) mixture, 1.0%. The higher bioavailability with chitosan hydrochloride compared to C934P and FNaC934P indicates that for buserelin the intestinal transmucosal transport enhancing effect of the polymer plays a more dominant role than the protection against proteases such as alpha-chymotrypsin. CONCLUSIONS: The mucoadhesive polymers carbomer 934P and chitosan hydrochloride are able to enhance the intestinal absorption of buserelin in vivo in rats, and may therefore be promising excipients in peroral delivery systems for peptide drugs.

Acrylic Resins↗
PubMed2006

Intestinal absorption of Stemona alkaloids in a Caco-2 cell model.

The intestinal absorption of neotuberostemonine and neostenine, two major bioactive alkaloids of the commonly used antitussive traditional Chinese medicine Stemona tuberosa Lour, was investigated using a Caco-2 monolayer model. Both alkaloids exhibited a high absorptive permeability which was higher for neostenine [P(app(AB)) = 12.03 +/- 1.14 x 10 (-6) cm/s] than for neotuberostemonine [P(app(AB)) = 9.27 +/- 0.79 x 10 (-6) cm/s], indicating that they are likely to be well absorbed and orally active. Furthermore, both alkaloids were identified to be the substrates of P-glycoprotein and have a transport preference from the basolateral to apical direction with efflux ratios between 2 and 3. Cyclosporin A dose-dependently inhibited the secretory permeability of these alkaloids and abolished their active efflux transport.

Alkaloids↗
PubMed1989

Fat intestinal absorption in the catfish--a histochemical study in glycol methacrylate embedded tissue.

The intestinal absorption of lipids was investigated in plastic sections from glycol methacrylate embedded intestine after fat administration. In the catfish, the lipids are absorbed by the enterocytes of the proximal intestinal segment, thus forming fat cytoplasmic inclusions that were demonstrated by Sudan black B staining. The histochemical characterization of lipids by the Nile blue sulphate test revealed the neutral or triglyceride nature of the cytoplasmic droplets, both after the corn oil and oleic acid feeding. There is lipid accumulation in the lamina propria and lymphatic vessels.

Animals↗
PubMed1987

Intestinal absorption of two glucose analogues in rats of different ages.

Intestinal absorption of nutrients and xenobiotics has been suggested to change during aging. Transport processes were examined using nonmetabolizable glucose analogues as markers in an in situ single pass intestinal perfusion procedure. Male Fischer 344 rats of 2, 4, 10, 16, and 27 months of age were used in this study. At least 7 rats were used per age group. Net active and passive transport were estimated using 0.85% NaCl solutions containing [14C]-3-O-methylglucose (3OMG) and [3H]-2-deoxy-D-glucose (2DG) and phenol red as nonabsorbed volume marker. Rats were anesthetized and approximately 30 cm of jejunum was perfused for 30 min. Final glucose analogue concentrations were corrected for volume changes, and compared with initial concentrations. Changes in marker concentrations were normalized to the dry weight of the perfused intestinal segment. Concurrent exposure to both glucose analogues allowed simultaneous monitoring of active and passive components. Under these conditions, there was no significant change in the net transport of 2DG, a compound absorbed by nonspecific processes (range 17-33 mumoles/g/h). In the same animals, the rate of net 3OMG absorption, an actively transported compound, was generally an order of magnitude greater than 2DG. In addition, net 3OMG absorption was significantly (p less than .05) decreased in the 16- and 27-month-old rats (237 and 181 mumoles/g/h) compared with the 2-, 4- and 10-month-old animals (325, 364 and 398 mumoles/g/h, respectively). There appears to be a gradual decrease in net active transport of glucose with age. The mechanism responsible for this age-related change remains to be explained.

3-O-Methylglucose↗
PubMed1995

Effects of folic acid and pyrimethamine, a dihydrofolate reductase inhibitor, on intestinal absorption of folates in rats.

Oral co-administration of folic acid (pteroylglutamic acid, PteGlu) potentiates the decrease of plasma 5-methyltetrahydrofolic acid (5-CH3-H4PteGlu) concentration induced by pyrimethamine (PYR) in rats. To clarify the mechanisms of this potentiated decrease, we examined the effects of PteGlu and PYR on intestinal absorption of folates in rat jejunum loops, because plasma 5-CH3-H4PteGlu concentration is maintained by enterohepatic circulation of folates. The intestinal absorption of 5-[14C]CH3-H4PteGlu was inhibited by PteGlu, but not by PYR. The absorption of [3H]PteGlu was inhibited by reduced folates that exist in bile. These findings indicate that PteGlu competes with the bile reduced folates for the intestinal transport system. The bile secretion of reduced folates was also examined to observe the conversion of absorbed PteGlu to reduced folates in the liver in the presence of PYR. The bile secretion of reduced folates increased drastically after the administration of PteGlu alone, but not after the administration of PteGlu with PYR. These facts suggest that the absorbed PteGlu was not converted to reduced folates in the liver due to PYR. In conclusion, the potentiated decrease of plasma 5-CH3-H4PteGlu concentration must have resulted from a combination of the following two factors: the inhibition of reabsorption of bile reduced folates by PteGlu and the inhibition of PteGlu conversion to reduced folates in the liver by PYR.

Animals↗
PubMed2004

Comparative in situ study of the intestinal absorption of aluminum, manganese, nickel, and lead in rats.

This comparative study of the intestinal absorption of four toxic metals (aluminum, manganese, nickel, and lead) carried out in rats using the in situ intestinal perfusion technique was able to measure the partition of each metal between the intestine (intestinal retention), the blood circulation, and target tissues after 1 h. The perfused metal solutions were at concentrations likely to occur during oral intoxication. It was found that aluminum (48 and 64 mM), even as a citrate complex, crossed the brush border with difficulty (0.4% of the perfused amount); about 60% of this was retained in the intestine and the remainder was found in target tissues (about 36%). Conversely, lead (4.8-48 microM) penetrated the intestine more easily (about 35% of the perfused amount), was slightly retained (about 12% of the input), and was soon found in the tissues (about 58% of the input) and to a lesser degree in circulation (about 29%). Within the same concentration range, nickel and manganese showed certain similarities, such as a reduced crossing of the brush border proportional to the increase in the concentration perfused (0.17-9.5 mM). There was similar intestinal retention and absorption (about 80% and 20% of the input, respectively). Manganese crossed the brush border more easily and was diffused more rapidly into tissues. Finally, the addition of equimolar amounts of iron (4.7 mM) produced opposite effects on the absorption of the two elements, inhibiting manganese and showing a trend to increase in nickel absorption. This could be the result of competition between Fe2+ and Mn2+ for the same transcellular transporters and the slight predominance of paracellular mechanism in the event of "Fe2+-Ni2+" association.

Aluminum↗
PubMedDate not supplied

Non-starch polysaccharides extracted from seaweed can modulate intestinal absorption of glucose and insulin response in the pig.

We have investigated the possible effects of algal polysaccharides on postprandial blood glucose and insulin responses in an animal model, the pig. Three seaweed fibres of different viscosities, extracted from Palmaria palmata (PP), Eucheuma cottonii (EC), or Laminaria digitata (LD), were compared to purified cellulose (CEL). Blood glucose and plasma insulin levels were monitored and intestinal absorption quantified for 8 h following a high carbohydrate test-meal supplemented with 5% fibre. Digestive contents were also sampled, 5 h postprandial. As compared to CEL, PP had no effect on glucose and insulin responses. The latter decreased with EC, but glucose absorption balance was not modified. LD addition resulted in a dramatically reduced glucose absorption balance, accompanied by a higher amount of starch left in the small intestine. Among polysaccharides tested, only the highly viscous alginates could affect intestinal absorption of glucose and insulin response.

Animals↗
PubMed1992

Mechanisms of intestinal absorption of the antibiotic, fosfomycin, in brush-border membrane vesicles in rabbits and humans.

In order to clarify the mechanism of intestinal absorption of an antibiotic, fosfomycin (FOM), the uptakes of FOM by rabbit and human small intestinal brush-border membrane vesicles (BBMV) were studied. The initial uptake of FOM by BBMV at 15 s was saturable at a higher concentration of FOM. The kinetic parameters at 37 degrees C of the saturable uptake expressed by the Michaelis-Menten equation were Kt = 5.17 mM and Jmax = 3.88 nmol/15 s/mg protein for rabbits, and Kt = 4.03 mM and Jmax = 1.90 nmol/15 s/mg protein for humans. The most efficient uptake was observed in the presence of both inward-directed Na(+)- and H(+)-gradients in both mammals. The uptake of FOM was inhibited by inorganic phosphate, FOM glycol which is a degradation product of FOM in the gastric juice and specific inhibitors of phosphate transport such as arsenate and phosphonoacetic acid. These findings confirmed that FOM absorption from rabbit and human small intestines is associated with the phosphate transport system. These transport phenomena of FOM are in close agreement with those obtained previously in rat BBMV studies. Judging from the results obtained for three mammalian species, rat, rabbit and human, it was concluded that carrier-mediated transport via the phosphate transport system is a very important pathway of intestinal absorption of FOM.

Animals↗
PubMed2003

Potential utility of various protease inhibitors for improving the intestinal absorption of insulin in rats.

The aim of the investigation was to study the effects of protease inhibitors on the absorption of insulin in-situ from closed small and large intestinal loops in rats and to investigate the mechanism of various protease inhibitors in different intestinal loops. The intestinal absorption of insulin was evaluated by its hypoglycaemic effect and serum insulin level in the presence or absence of luminal contents. No marked hypoglycaemic effect was observed after administration of insulin alone in either region in the presence or absence of luminal contents. A significant hypoglycaemic effect of insulin was obtained in the large intestinal loop in the presence or absence of luminal contents when insulin was co-administered with bacitracin (20, 30 mM), sodium glycocholate (20, 40 mM), bestatin (29 mM), leupeptin (21 mM) and cystatin (0.8 mM). In contrast, there was no hypoglycaemic effect in the small intestinal loop in the presence of luminal contents following small intestinal co-administration of insulin with these protease inhibitors. The effectiveness of protease inhibitors was susceptible to their categories, concentrations and activity of proteolytic enzymes in different regions. The degree of improving insulin absorption in intestine was in the order of leupeptin>sodium glycocholate>bacitracin>bestatin>cystatin. At the same time, the percutaneous enhancement effect was observed in the presence of either sodium glycocholate or bacitracin. These results suggest that protease inhibitors could increase the insulin efficacy more effectively in the large intestine than in the small intestine.

Animals↗
PubMed1994

The effect of intestinal hypoperfusion on intestinal absorption and permeability during cardiopulmonary bypass.

BACKGROUND/AIMS: Mean arterial pressure is reduced during hypothermic cardiopulmonary bypass. The aim of this study was to assess whether this was associated with intestinal hypoperfusion and whether it affected intestinal absorption and permeability. METHODS: Twenty-six patients undergoing coronary artery bypass grafting underwent an intestinal absorption-permeability test involving ingestion of 3-O-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose. Ingestion took place 2 days before, within 3 hours, and 5 days after hypothermic cardiopulmonary bypass. Hemodynamic parameters and gastric mucosal laser Doppler blood flow were measured perioperatively in eight patients. RESULTS: Hypothermic (28 degrees C), nonpulsatile cardiopulmonary bypass resulted in a 25% reduction in mean blood pressure, 10% reduction in cardiac index, and a 46% reduction in gastric mucosal laser Doppler blood flow. There was 85.4%, 85.5%, and 73.6% reduction (P < 0.01) in active (3-O-methyl-D-glucose) and passive (D-xylose) carrier-mediated transport and passive, nonmediated transcellular (L-rhamnose) transport in the immediate postoperative period, respectively. The differential urine excretion of lactulose/L-rhamnose increased sixfold. All parameters returned to control levels by the fifth postoperative day. CONCLUSIONS: Cardiopulmonary bypass, while maintaining generally acceptable levels of hemodynamic performance, is associated with significant intestinal hypoperfusion and malabsorption of monosaccharides, which may have implications for enteral drug treatment in the immediate postoperative period.

Adult↗