共查询到20条相似文献,搜索用时 15 毫秒
1.
D. Krüger R. Grossklaus M. Herold S. Lorenz L. Klingebiel 《Cellular and molecular life sciences : CMLS》1992,48(8):733-740
Using data obtained with a dye marker and the gavage technique, the kinetics of gastrointestinal transit of different loads of sugar substitutes (maltitol, sorbitol) and sugar (sucrose) in the rat were analysed using a linear multicompartmental model over a range from the realistic to the non-physiologic high, of carbohydrate intake levels and using only a few experimental time points. The model gave detailed insight into intestinal propulsion and gastrocecal transit time. Rate constants of transport between the compartments investigated were determined; they showed characteristics which could be related to the substance and the dosage administered. Analyses of the gastrointestinal content and calculations of the intestinal net water movement showed that the digestibility and absorption of the disaccharide sugar alcohol, maltitol, in the small gut depended inversely on the dose ingested. For all substances tested, caloric availability in the small intestine was calculated. At a physiological low level of maltitol intake, the results also indicated an insignificant calorie-saving effect in comparison to sucrose, an effect based mainly on the slow absorption rate of the maltitol cleavage product sorbitol. 相似文献
2.
Ecological and evolutionary implications of digestive processes: Bird preferences and the sugar constituents of floral nectar and fruit pulp 总被引:3,自引:0,他引:3
C. Martínez del Rio H. G. Baker I. Baker 《Cellular and molecular life sciences : CMLS》1992,48(6):544-551
Plants pollinated and dispersed by different groups of birds offer different kinds of sugars in nectar and fruit pulp. The preferences and physiological traits of avian pollinators and seed dispersers are broadly correlated with the sugar composition of the nectar and fruit that they feed on and appear to have influenced the evolution of the sugar composition of the rewards that plants offer. Hummingbirds prefer sucrose whereas many nectar- and fruit-eating passerines prefer glucose and fructose. Preference for hexoses in passerines seems to be associated with poor sucrose assimilation resulting from two physiological mechanisms: lack of intestinal sucrase activity and fast passage rates. Sucrase activity absence appears to be restricted to a single phylogenetic group (the sturnid-muscicapid lineage). Fast passage rates seem to be characteristic of many small frugivores and to hinder the assimilation of complex nutrients that require hydrolysis before absorption. Hummingbirds have extremely specialized digestive traits that allow them to assimilate sucrose at high rates and with extremely high efficiency. These specialized digestive traits appear not to be present in many nectar-feeding passerines. 相似文献
3.
J. C. McElnay P. F. D'Arcy J. K. Leonard 《Cellular and molecular life sciences : CMLS》1982,38(5):605-607
Summary A study was made of the effect of 6 commonly used gastrointestinal preparations on the absorption of propranolol using an
in vitro experimental model. The constituents examined were activated dimethicone, aluminium hydroxide gel, bismuth carbonate,
kaolin, magnesium carbonate, and magnesium trisilicate. A slight decreased propranolol absorption was given by kaolin (−13.0%),
the other components showed smaller effects ranging from −6.8% to +6.6%. None of the results were statistically significantly
different from control absorption values.
Acknowledgment. We are grateful to I.C.I. Ltd, Macclesfield, England, for the gift of propranolol hydrochloride and to Galen
Ltd, Craigavon, Northern Ireland, for the gift of dimethicone. 相似文献
4.
The inhibitory action of L-leucine on the intestinal absorption of D-glucose and D-galactose, as well as the inhibitory action of D-galactose on the absorption of L-leucine at various concentrations by rat small intestine has been studied. The further effect was more clearly evidenced when the medium was perfunded through the intestine in a closed circuit system using a peristaltic pump. 相似文献
5.
A study was made of the effect of 4 constituents of antacid preparations on the absorption of the coumarin derivate warfarin sodium using an in vitro experimental model. The constituents tested were activated dimethiocone (a silicone) magnesium trisilicate, bismuth carbonate and the adsorbant, kaolin. Slight decreased intestinal absorption was shown by magnesium trisilicate (19%) and bismuth carbonate (7%), the other 2 components showing no effects. 相似文献
6.
J. C. McElnay D. W. G. Harron P. F. D'Arcy P. S. Collier 《Cellular and molecular life sciences : CMLS》1979,35(10):1359-1360
Summary A study was made of the effect of 4 constituents of antacid preparations on the absorption of the coumarin derivate warfarin sodium using an in vitro experimental model. The constituents tested were activated dimethicone (a silicone) magnesium trisilicate, bismuth carbonate and the adsorbant, kaolin. Slight decreased intestinal absorption was shown by magnesium trisilicate (19%) and bismuth carbonate (7%), the other 2 components showing no effects. 相似文献
7.
Summary The inhibitory action ofl-leucine on the intestinal absorption ofd-glucose andd-galactose, as well as the inhibitory action ofd-galactose on the absorption ofl-leucine at various concentrations by rat small intestine has been studied. The further effect was more clearly evidenced
when the medium was perfunded through the intestine in a closed circuit system using a peristaltic pump. 相似文献
8.
Summary There is now considerable evidence implicating several peptides in the control of gastrointestinal epithelial cell proliferation and cell renewal. While some of these may act directly, many may be involved in regulating the powerful trophic effects of the intake and digestion of foold on the gut epithelium.—Several peptides have been associated with the regulation of intestinal cell proliferation. There is little doubt that gastrin is trophic to the stomach, but, its role in the rest of the gastrointestinal tract is debatable. Enteroglucagon has often been associated with increased intestinal epithelial proliferation, but at the moment all the evidence for this is circumstantial. The effects of peptide YY and bombesin warrant further study. The availability of recombinant epidermal growth factor (EGF) has recently enabled us to demonstrate a powerful trophic response to infused EGF throughout the gastrointestinal tract. The increasing availability of peptides will eventually allow the rigorous in vivo evaluation of the trophic role of these potentially very important peptides. 相似文献
9.
Peptides and epithelial growth regulation 总被引:1,自引:0,他引:1
There is now considerable evidence implicating several peptides in the control of gastrointestinal epithelial cell proliferation and cell renewal. While some of these may act directly, many may be involved in regulating the powerful trophic effects of the intake and digestion of food on the gut epithelium. Several peptides have been associated with the regulation of intestinal cell proliferation. There is little doubt that gastrin is trophic to the stomach, but, its role in the rest of the gastrointestinal tract is debatable. Enteroglucagon has often been associated with increased intestinal epithelial proliferation, but at the moment all the evidence for this is circumstantial. The effects of peptide YY and bombesin warrant further study. The availability of recombinant epidermal growth factor (EGF) has recently enabled us to demonstrate a powerful trophic response to infused EGF throughout the gastrointestinal tract. The increasing availability of peptides will eventually allow the rigorous in vivo evaluation of the trophic role of these potentially very important peptides. 相似文献
10.
M. Lourau 《Cellular and molecular life sciences : CMLS》1961,17(9):422-423
Summary A sublethal dose of X-rays, delivered to guinea-pigs 14 days before a glucose absorption test, alters the pattern of water exchange between the blood and the gastric cavity. The normal dilution, which proves to be a main factor in the regulation of the intestinal absorption of sugar, is no longer achieved. 相似文献
11.
The direct effect of somatostatin on the absorption of 3-oxymethylglucose in epithelial cells isolated from the small intestine of chicken was studied. The presence of somatostatin in the incubation medium at concentrations of 3.5 X 10(-8) M and 7 X 10(-8) M produced significant dose-dependent increases in the accumulation of sugar in the enterocytes. This effect might be due to an increase in the cell membrane permeability caused by hormone action. 相似文献
12.
Summary Loops of rat's small intestine have been perfused with 5% glucose solution at different flow rates. The absorption of glucose has been investigated. The results showed that, with increasing flow rates, absorption rate of glucose is also increased. Therefore contact time seems to be no limiting factor in intestinal absorption.
Mit Unterstützung des Österr. Fonds zur Förderung der wissenschaftlichen Forschung, Projekt Nr. 650. 相似文献
Mit Unterstützung des Österr. Fonds zur Förderung der wissenschaftlichen Forschung, Projekt Nr. 650. 相似文献
13.
Intestinal tissue mass was significantly reduced throughout the gastrointestinal tract (p less than 0.001) of intravenously fed (TPN) rats. Urogastrone-epidermal growth factor, (URO-EGF), reversed these changes. Although plasma enteroglucagon and gastrin levels showed a small increase with URO-EGF, this was far less than the gut tissue weight change, suggesting that it was unlikely that they were involved in modulating the proliferative response of the intestine to URO-EGF. Peptide tyrosine tyrosine (PYY) levels were however significantly increased by URO-EGF, indicating that PYY may possibly have a role in the modulation of intestinal cell proliferation. 相似文献
14.
M Riottot E Sacquet C Leprince C Méjean 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1977,284(4):309-311
When Rats were fed a lactose containing diet, both the absorption rate of sodium taurocholate at the level of ileum and the contents of bile acids of the small intestine were increased. On the contrary, feeding of lactose did not modify the daily fecal excretion of bile acids. It therefore appears that dietary lactose increases the intestinal pool of bile acids by increasing their ileal absorption rate and that this effect of lactose is not subordinated to a modification of bile acid synthesis. 相似文献
15.
V. Balatková E. Hrabětová J. Tupý 《Cellular and molecular life sciences : CMLS》1976,32(10):1255-1256
Summary The substitution of sucrose in the nutrient medium for in vitro pollinated placentae by glucose and fructose favours seed formation and considerably enhances the germination of seeds just attaining maturity. This effect of invert sugar was wholly suppressed in the mixture with two parts of sucrose. 相似文献
16.
Summary The direct effect of somatostatin on the absorption of 3-oxymethylglucose in epithelial cells isolated from the small intestine of chicken was studied. The presence of somatostatin in the incubation medium at concentrations of 3.5×10–8 M and 7×10–8 M produced significant dose-dependent increases in the accumulation of sugar in the enterocytes. This effect might be due to an increase in the cell membrane permeability caused by hormone action. 相似文献
17.
Amylin given by central or peripheral routes decreases gastric emptying and intestinal transit in the rat 总被引:1,自引:0,他引:1
G. clementi A. Caruso V. M. C. Cutuli E. de Bernardis A. Prato M. Amico-Roxas 《Cellular and molecular life sciences : CMLS》1996,52(7):677-679
The effect of rat amylin on gastric emptying and intestinal transit in the rat was examined. Amylin administered intracerebroventricularly (1, 2, 2.5 or 4 g/rat) produced the maximal decrease in gastric emptying and intestinal transit at the dose of 2.5 g/rat. Higher doses produced a lower effect. Peripheral administration (25, 50 or 100 g/kg) produced dose-dependent effects. Pre-treatment with neostigmine blocked the effect of amylin when it was centrally injected, while the effect of amylin given peripherally was partially reduced. Pre-treatment with domperidone decreased the inhibitory effect of peripherally injected amylin, but no effect was observed when the peptide was centrally injected. 相似文献
18.
Takuya Suzuki 《Cellular and molecular life sciences : CMLS》2013,70(4):631-659
The gastrointestinal epithelium forms the boundary between the body and external environment. It effectively provides a selective permeable barrier that limits the permeation of luminal noxious molecules, such as pathogens, toxins, and antigens, while allowing the appropriate absorption of nutrients and water. This selective permeable barrier is achieved by intercellular tight junction (TJ) structures, which regulate paracellular permeability. Disruption of the intestinal TJ barrier, followed by permeation of luminal noxious molecules, induces a perturbation of the mucosal immune system and inflammation, and can act as a trigger for the development of intestinal and systemic diseases. In this context, much effort has been taken to understand the roles of extracellular factors, including cytokines, pathogens, and food factors, for the regulation of the intestinal TJ barrier. Here, I discuss the regulation of the intestinal TJ barrier together with its implications for the pathogenesis of diseases. 相似文献
19.
J. C. McElnay D. W. G. Harron P. F. D'Arcy M. R. G. Eagle 《Cellular and molecular life sciences : CMLS》1979,35(1):94-94
Summary A study was made of the effect of activated dimethicone on the absorption of digoxin in relation to other commonly used antacid constituents using an in vitro experimental model. Dimethicone was found not to affect the absorption of digoxin in relation to aluminium hydroxide, bismuth carbonate, light magnesium carbonate and magnesium trisilicate whose effects on the absorption of digoxin were in agreement with values reported in the literature. 相似文献
20.
Paneth cells (PCs) were described over a century ago as granulated cells located at the base of small intestinal crypts,
the 'crypts of Lieberkühn.' Various histochemical staining procedures were developed that identified PCs based on their distinctive
granule staining pattern. Early on, PCs were proposed to perform a specialized function other than absorption of digested
nutrients, the predominant task of the small intestinal epithelium. Since then, many constituents of the PC granules have
been biochemically characterized. The presence of various granule-associated antimicrobial substances and their release upon
microbial challenge suggest that PCs function as specialized defense cells in the small intestine. Altered resistance to microbial
infection in animal models with disrupted or augmented PC function provides further support for the host defense role of PCs.
Other PC components suggest that PCs may also participate in the regulation of lumenal ionic composition, crypt development,
digestion, and intestinal inflammation.
Received 6 June 2001; received after revision 26 July 2001; accepted 27 July 2001 相似文献