Glucose flux from dietary disaccharides: all sugars are not absorbed at equal rates

1991 ◽  
Vol 261 (5) ◽  
pp. G818-G822 ◽  
Author(s):  
L. A. Heitlinger ◽  
B. U. Li ◽  
R. D. Murray ◽  
H. J. McClung ◽  
H. R. Sloan ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Glucose Transporter ◽  
Short Circuit ◽  
Hydrolytic Enzyme ◽  
Short Circuit Current ◽  
Glucose Absorption ◽  
Glucose Flux ◽  
Free Glucose ◽  
Hydrolysis Of

Considerable discrepancies exist in the literature regarding the rates of glucose absorption from the common dietary disaccharides, lactose, maltose, and sucrose. This study compared the unidirectional flux of glucose derived from dietary disaccharides with that of their constituent monosaccharides in vitro. Lactose-stimulated short-circuit current (Isc) and mucosal-to-serosal flux (Jm----s) were lower than that of an equimolar glucose-galactose mixture and were phlorizin inhibitable. Maltose- and glucose-stimulated Isc were similar, but Jm----s of glucose derived from the hydrolysis of maltose was lower than that of free glucose. Sucrose-stimulated Isc and Jm----s were similar to that of an equimolar glucose-fructose mixture. Isc and Jm----s of glucose from both maltose and sucrose were phlorizin and acarbose inhibitable. We conclude that the rate of glucose uptake from disaccharides is less than or equal to that of free glucose and is dependent on the glucose source. We speculate that regulation of glucose uptake from disaccharides can occur at three sites: the hydrolytic enzyme, the glucose transporter, and the tight junctions.

Glucose Transport by the In Vitro Perfused Midgut of the Blue Crab, Callinectes Sapidus

1986 ◽  
Vol 123 (1) ◽  
pp. 325-344 ◽  
Author(s):  
KA HOU CHU
Keyword(s):  
Callinectes Sapidus ◽  
Glucose Absorption ◽  
Metabolic Inhibitors ◽  
Kinetic Characteristics ◽  
Active Mechanism ◽  
Glucose Flux ◽  
Sodium Dependent ◽  
Free Glucose ◽  
Thin Layer Chromatographic Analysis

1. The midgut of Callinectes sapidus is capable of net transmural glucose absorption. 2. The mucosal glucose influx by the midgut has a sodium-dependent, saturable component and a sodium-independent, non-saturable counterpart. 3. The unidirectional mucosal to serosal flux and the mucosal influx of glucose are depressed by metabolic inhibitors, the presence of mucosal phlorizin or serosal ouabain. 4. The low rate of net transmural glucose flux and the kinetic characteristics of mucosal influx suggest that the midgut does not play an important role in total nutrient absorption. 5. Thin layer chromatographic analysis shows that most of the glucose appears as phosphorylated forms upon entering the midgut, suggesting that the efflux of free glucose across the serosal border requires an active mechanism.

scholarly journals Ecklonia cavaInhibits Glucose Absorption and Stimulates Insulin Secretion in Streptozotocin-Induced Diabetic Mice

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Hye Kyung Kim
Keyword(s):  
Insulin Secretion ◽  
Protein Expression ◽  
Glucose Uptake ◽  
Glucose Transporter ◽  
Islet Cells ◽  
Glucose Absorption ◽  
Oral Glucose ◽  
Diabetic Mice ◽  
Glucose Transporter 1

Aims of study. Present study investigated the effect ofEcklonia cava(EC) on intestinal glucose uptake and insulin secretion.Materials and methods. Intestinal Na+-dependent glucose uptake (SGU) and Na+-dependent glucose transporter 1 (SGLT1) protein expression was determined using brush border membrane vesicles (BBMVs). Glucose-induced insulin secretion was examined in pancreatic β-islet cells. The antihyperglycemic effects of EC, SGU, and SGLT1 expression were determined in streptozotocin (STZ)-induced diabetic mice.Results. Methanol extract of EC markedly inhibited intestinal SGU of BBMV with the IC50value of 345 μg/mL. SGLT1 protein expression was dose dependently down regulated with EC treatment. Furthermore, insulinotrophic effect of EC extract was observed at high glucose media in isolated pancreatic β-islet cellsin vitro. We next conducted the antihyperglycemic effect of EC in STZ-diabetic mice. EC supplementation markedly suppressed SGU and SGLT1 abundance in BBMV from STZ mice. Furthermore, plasma insulin level was increased by EC treatment in diabetic mice. As a result, EC supplementation improved postprandial glucose regulation, assessed by oral glucose tolerance test, in diabetic mice.Conclusion. These results suggest that EC play a role in controlling dietary glucose absorption at the intestine and insulinotrophic action at the pancreas contributing blood glucose homeostasis in diabetic condition.

Action of 2-deoxy-D-glucose on frog gastric mucosa

1965 ◽  
Vol 209 (3) ◽  
pp. 461-466 ◽  
Author(s):  
George Sachs ◽  
R. Shoemaker ◽  
B. I. Hirschowitz
Keyword(s):  
Gastric Mucosa ◽  
Acid Secretion ◽  
Glucose Uptake ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Potential Difference ◽  
Atp Levels

2-Deoxyglucose (2-DG) has been found to inhibit chloride and acid secretion by the in vitro frog mucosa, with a fall in short-circuit current and potential difference and a rise in resistance. The ATP levels and phosphohexoisomerase activity were essentially unchanged following 2-DG treatment. 3-Methyl-O-glucose uptake was reduced by about 50% following preincubation with 2-DG. The O2 consumption was only slightly reduced with 10 mmoles 2-DG, but the CO2 ratio from glucose-6-C14/glucose-1-C14 fell from 0.98 to 0.37, indicating activation of the hexosemonophosphate (HMP) shunt.

OSMOTIC INHIBITION OF THE NATRIFERIC RESPONSE OF THE TOAD URINARY BLADDER TO VASOPRESSIN

1975 ◽  
Vol 67 (1) ◽  
pp. 119-125
Author(s):  
P. J. BENTLEY
Keyword(s):  
Urinary Bladder ◽  
Water Movement ◽  
Short Circuit ◽  
Electrical Potential ◽  
Short Circuit Current ◽  
Toad Bladder ◽  
Toad Urinary Bladder ◽  
Electrical Potential Difference ◽  
Osmotic Gradient

SUMMARY The electrical potential difference and short-circuit current (scc, reflecting active transmural sodium transport) across the toad urinary bladder in vitro was unaffected by the presence of hypo-osmotic solutions bathing the mucosal (urinary) surface, providing that the transmural flow of water was small. Vasopressin increased the scc across the toad bladder (the natriferic response), but this stimulation was considerably reduced in the presence of a hypo-osmotic solution on the mucosal side, conditions under which water transfer across the membrane was also increased. This inhibition of the natriferic response did not depend on the direction of the water movement, for if the osmotic gradient was the opposite way to that which normally occurs, the response to vasopressin was still reduced. The natriferic response to cyclic AMP was also inhibited in the presence of an osmotic gradient. Aldosterone increased the scc and Na+ transport across the toad bladder but this response was not changed when an osmotic gradient was present. The physiological implications of these observations and the possible mechanisms involved are discussed.

Protein kinase C potentiates cAMP-stimulated mouse duodenal mucosal bicarbonate secretion in vitro

2004 ◽  
Vol 286 (5) ◽  
pp. G814-G821 ◽  
Author(s):  
Bi-Guang Tuo ◽  
Jimmy Y. C. Chow ◽  
Kim E. Barrett ◽  
Jon I. Isenberg
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Duodenal Mucosa ◽  
Bicarbonate Secretion ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ussing Chambers ◽  
Duodenal Bicarbonate Secretion

PKC has been shown to regulate epithelial Cl- secretion in a variety of models. However, the role of PKC in duodenal mucosal bicarbonate secretion is less clear. We aimed to investigate the role of PKC in regulation of duodenal mucosal bicarbonate secretion. Bicarbonate secretion by murine duodenal mucosa was examined in vitro in Ussing chambers using a pH-stat technique. PKC isoform expression and activity were assessed by Western blotting and in vitro kinase assays, respectively. PMA (an activator of PKC) alone had no effect on duodenal bicarbonate secretion or short-circuit current ( Isc). When PMA and dibutyryl-cAMP (db-cAMP) were added simultaneously, PMA failed to alter db-cAMP-stimulated duodenal bicarbonate secretion or Isc ( P > 0.05). However, a 1-h preincubation with PMA potentiated db-cAMP-stimulated duodenal bicarbonate secretion and Isc in a concentration-dependent manner (from 10-8 to 10-5M) ( P < 0.05). PMA preincubation had no effects on carbachol- or heat-stable toxin-stimulated bicarbonate secretion. Western blot analysis revealed that PKCα, -γ, -ϵ, -θ, -μ, and -ι/λ were expressed in murine duodenal mucosa. Ro 31–8220 (an inhibitor active against PKCϵ, -α, -β, and -γ), but not Gö 6983 (an inhibitor active against PKCα, -γ, -β, and -δ), reversed the potentiating effect of PMA on db-cAMP-stimulated bicarbonate secretion. PMA also time- and concentration-dependently increased the activity of PKCϵ, an effect that was prevented by Ro 31–8220 but not Gö 6983. These results demonstrate that activation of PKC potentiates cAMP-stimulated duodenal bicarbonate secretion, whereas it does not modify basal secretion. The effect of PKC on cAMP-stimulated bicarbonate secretion is mediated by the PKCϵ isoform.

scholarly journals Antihyperglycemic and Antilipidemic Effects of the Ethanol Extract Mixture of Ligularia fischeri and Momordica charantia in Type II Diabetes-Mimicking Mice

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Hyun Jin Baek ◽  
Yong Joon Jeong ◽  
Jeong Eun Kwon ◽  
Jong Sung Ra ◽  
Sung Ryul Lee ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Uptake Rate ◽  
Glucose Transporter ◽  
Synergistic Effects ◽  
Momordica Charantia ◽  
C2c12 Cells ◽  
Peroxisome Proliferator ◽  
Glucose Uptake Rate ◽  
Ligularia Fischeri

The extract of the Momordica charantia fruit (MCE) is recognized as an alternative treatment for diabetes. The extract of Ligularia fischeri leaves (LFE) is traditionally used as a folk medicine for treating inflammatory diseases in Korea as well. In this study, we investigated the synergistic effect of MCE combined with LFE on antihyperglycemic and antihyperlipidemic potentials. Based on the α-glucosidase inhibitory effect and promotion of adipocyte differentiation in the 3T3-L1 cell line, the MLM was prepared with MCE:LFE (8:2 weight:weight). MLM showed the synergistic effects in the promotion of the glucose uptake rate, suppression of dipeptidyl peptidase-4 (DPP-4) mRNA expression, upregulation of an insulin receptor substrate and glucose transporter type-4 expression, and an increase in insulin-associated signaling in C2C12 cells. In addition, the efficacy of peroxisome proliferator-activated receptor-γ agonism and glucose uptake rate by MLM supplementation was significantly enhanced in vitro. Then, the antihyperglycemic and antihyperlipidemic effects of MCE, LFE, and MLM at the dose of 50, 100, and 200 mg/kg/day (n = 6 per each group) were determined in streptozotocin (STZ)-insulted mice fed an atherogenic diet (ATH) for 4 weeks. In addition, MLM (50, 100, and 200 mg/kg/day, n = 5 per each group) was supplemented in ATH-fed db/db mice for 10 weeks. Compared with MCE or LFE alone, MLM supplementation led to a more significant reduction of glucose levels in both STZ/ATH and db/db/ATH mice as well as lowered lipid profiles in STZ/ATH mice. In addition, the stimulation of islet of Langerhans regeneration was more pronounced by MLM supplementation in both mice models. In conclusion, antihyperglycemic and antihyperlipidemic effects were strengthened by the combined extracts of L. fischeri and M. charantia (MLM) in diabetes-mimicking mice.

Cellular pathways mediating tachykinin-evoked secretomotor responses in guinea pig ileum

1997 ◽  
Vol 273 (5) ◽  
pp. G1127-G1134 ◽  
Author(s):  
W. MacNaughton ◽  
B. Moore ◽  
S. Vanner
Keyword(s):  
Guinea Pig ◽  
Receptor Agonist ◽  
Short Circuit ◽  
Ussing Chamber ◽  
Short Circuit Current ◽  
Neurokinin A ◽  
Guinea Pig Ileum ◽  
Cellular Pathways ◽  
20 Nm

This study characterized tachykinin-evoked secretomotor responses in in vitro submucosal and mucosal-submucosal preparations of the guinea pig ileum using combined intracellular and Ussing chamber recording techniques. Superfusion of endogenous tachykinins substance P (SP), neurokinin A (NKA), and neurokinin B depolarized single submucosal neurons and evoked increased short-circuit current ( I sc) responses in Ussing chamber preparations. The NK1-receptor agonist [Sar9,Met(O2)11]SP [50% effective concentration (EC50) = 2 nM] depolarized all submucosal neurons examined. The NK3-receptor agonist senktide (EC50 = 20 nM) depolarized ∼50% of neurons examined, whereas the NK2-receptor agonist [Ala5,β-Ala8]NKA-(4—10) had no effect on membrane potential. [Sar9,Met(O2)11]SP and senktide evoked similar increases in I sc that were tetrodotoxin sensitive (91 and 100%, respectively) and were selectively blocked by the NK1antagonist CP-99,994 and the NK3antagonist SR-142801, respectively. Capsaicin-evoked increases in I sc were significantly inhibited (54%, P < 0.05) by CP-99,994 but not by SR-142801. Neither antagonist inhibited slow excitatory postsynaptic potentials. These findings suggest that tachykinin-evoked secretion in guinea pig ileum is mediated by NK1 and NK3 receptors on submucosal secretomotor neurons and that capsaicin-sensitive nerves release tachykinin(s) that activate the NK1 receptors.

Sodium transport by lamb proximal colon measured during early postnatal development

1982 ◽  
Vol 98 (1) ◽  
pp. 155-159 ◽  
Author(s):  
M. W. Smith ◽  
P. S. James
Keyword(s):  
Postnatal Development ◽  
Sodium Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Proximal Colon ◽  
Early Postnatal Development ◽  
The Third ◽  
Electrolyte Absorption ◽  
Chloride Absorption

SUMMARYProximal colons taken from lambs up to 3 weeks after birth were shown to transport both sodium and chloride from lumen to blood when incubated in vitro.Sodium transport fell into three phases during postnatal development. The first covered the period from birth to 3 days of age when sodium transport was high and equal to that calculated from measurement of short-circuit current. The second was seen in 5- and 7-day-old lambs where the short-circuit current was low and the net transport of sodium was negligible. The third was seen in 2-3-week-old lambs where sodium transport was high, but the short-circuit current was low.Chloride absorption by colons taken from 1-day-old lambs appeared to be in exchange for an anion, possibly bicarbonate. Chloride absorption by colons taken from 3-week-old lambs appeared to be electrogenie or coupled directly to the transport of sodium.A possible explanation for the failure of electrolyte absorption by colons taken from 5- and 7-day-old lambs is discussed.

Electron probe X-ray microanalysis of the effects of Bacillus thuringiensis var kurstaki crystal protein insecticide on ions in an electrogenic K+-transporting epithelium of the larval midgut in the lepidopteran, Manduca sexta, in vitro

1985 ◽  
Vol 74 (1) ◽  
pp. 137-152
Author(s):  
B.L. Gupta ◽  
J.A. Dow ◽  
T.A. Hall ◽  
W.R. Harvey
Keyword(s):  
Bacillus Thuringiensis ◽  
Manduca Sexta ◽  
Goblet Cell ◽  
Electron Probe ◽  
Apical Membrane ◽  
Short Circuit ◽  
Short Circuit Current ◽  
X Ray ◽  
Elemental Concentrations

An alkaline hydrolysate of Bacillus thuringiensis var kurstaki HD1 (Btk) parasporal crystals was administered at 25 micrograms ml-1 (f.c.) to isolated, short-circuited, midguts of tobacco hornworm (Manduca sexta) larvae. The short-circuit current (s.c.c.), a precise measure of K+ active transport, was inhibited by 78% in 10 min in Btk-treated midguts as compared to controls. The elemental concentrations of K, together with Na, Mg, P, S, Cl and Ca, as well as the water content, were determined by electron probe X-ray microanalysis (EPXMA) in the muscle cells, columnar cells and goblet cells, as well as in the extracellular goblet cavity and the bathing media. The average K concentration in the goblet cell cavity was 129 mmol/kg wet wt in control midguts but only 37 mmol/kg wet wt in Btk-treated midguts. The elemental concentrations, including that of K, in other cell compartments were much less affected by Btk, but a rise in total cell calcium is suggested. It has been previously suggested that in vitro Btk acts specifically on limited regions of the apical membrane of the midgut epithelial cells. The simplest interpretation of the EPXMA results would be that initially Btk interacts specifically with the goblet cell apical membrane, which bounds the goblet cavity and contains the K+ pump responsible for the s.c.c. and high transepithelial potential difference (p.d.). Such interaction results in a rapid disruption of K+ transport across the goblet cell apical membrane, leading to dissipation of the K+ gradient and loss of p.d. The histopathological changes previously reported by other workers would then be a consequence of K+ pump inhibition causing changes in the intracellular pH, Ca2+ etc. Some possible molecular bases for these specific interactions between Btk and cell membrane are discussed.

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