Evidence for Active Transport of the Dipeptide Glycylsarcosine by Hamster Jejunum in Vitro

1972 ◽  
Vol 43 (6) ◽  
pp. 907-911 ◽  
Author(s):  
Jill M. Addison ◽  
D. Burston ◽  
D. M. Matthews
Keyword(s):  
Active Transport ◽  
Uptake Mechanism ◽  
Dependent Process ◽  
Mucosal Cells

1. Glycylsarcosine, a peptide which is slowly hydrolysed by the intestine, is transported into the jejunal mucosal cells of the hamster by an active Na+-dependent process. 2. Uptake of glycylsarcosine is inhibited by l-methionyl-l-methionine but not by l-methionine, suggesting that l-methionyl-l-methionine and glycylsarcosine share an uptake mechanism which is independent of that for free methionine, and that l-methionyl-l-methionine may also enter the cells.

ACTIVE TRANSPORT OF ASCORBIC ACID IN ADRENAL CORTEX AND BRAIN CORTEX IN VITRO AND THE EFFECTS OF ACTH AND STEROIDS

1963 ◽  
Vol 41 (1) ◽  
pp. 597-604 ◽  
Author(s):  
Shail K. Sharma ◽  
R. M. Johnstone ◽  
J. H. Quastel
Keyword(s):  
Ascorbic Acid ◽  
Adrenal Cortex ◽  
Active Transport ◽  
Brain Cortex ◽  
Acid Uptake ◽  
Dependent Process ◽  
Brain Cortex Slices ◽  
Cortex Slices ◽  
Energy Dependent

Uptake of ascorbic acid-1-C14in brain cortex and adrenal cortex slices is an energy-dependent process. Concentration ratios (i.e. ratios of tissue ascorbic acid-1-C14to medium ascorbic acid-1-C14) greater than 4 have been obtained with both tissues in vitro. Ouabain as well as 2, 4-dinitrophenol suppresses ascorbic acid uptake into brain cortex slices.ACTH inhibits the uptake of ascorbic acid-1-C14in adrenal cortex, but not in brain cortex slices. The presence of glucose is necessary for the inhibition. Several cortical steroids, as well as adenosine-3′,5′-monophosphate, at small concentrations inhibit the uptake. The results are consistent with the interpretation that ACTH inhibits the uptake of ascorbic acid in the adrenal cortex through the steroids produced in its presence.

ACTIVE TRANSPORT OF ASCORBIC ACID IN ADRENAL CORTEX AND BRAIN CORTEX IN VITRO AND THE EFFECTS OF ACTH AND STEROIDS

1963 ◽  
Vol 41 (3) ◽  
pp. 597-604 ◽  
Author(s):  
Shail K. Sharma ◽  
R. M. Johnstone ◽  
J. H. Quastel
Keyword(s):  
Ascorbic Acid ◽  
Adrenal Cortex ◽  
Active Transport ◽  
Brain Cortex ◽  
Acid Uptake ◽  
Dependent Process ◽  
Brain Cortex Slices ◽  
Cortex Slices ◽  
Energy Dependent

Uptake of ascorbic acid-1-C14in brain cortex and adrenal cortex slices is an energy-dependent process. Concentration ratios (i.e. ratios of tissue ascorbic acid-1-C14to medium ascorbic acid-1-C14) greater than 4 have been obtained with both tissues in vitro. Ouabain as well as 2, 4-dinitrophenol suppresses ascorbic acid uptake into brain cortex slices.ACTH inhibits the uptake of ascorbic acid-1-C14in adrenal cortex, but not in brain cortex slices. The presence of glucose is necessary for the inhibition. Several cortical steroids, as well as adenosine-3′,5′-monophosphate, at small concentrations inhibit the uptake. The results are consistent with the interpretation that ACTH inhibits the uptake of ascorbic acid in the adrenal cortex through the steroids produced in its presence.

Active transport of iron to mucosal surface of rat jejunum

1975 ◽  
Vol 229 (3) ◽  
pp. 790-796 ◽  
Author(s):  
MJ Guy ◽  
D Schachter
Keyword(s):  
Active Transport ◽  
Protein Biosynthesis ◽  
Mucosal Surface ◽  
Metabolic Inhibitors ◽  
Reverse Direction ◽  
Distal Small Intestine ◽  
Mucosal Cells ◽  
Potential Gradients

Estimations of steady-state fluxes of divalent Fe across rat intestinal segments in vitro provide evidence for two active transport mechanisms. Segments of the distal small intestine transport the mineral against electrochemical potential gradients from the serosal to the mucosal surface. Active transport in the reverse direction was confirmed with segments of proximal duodenum. The distal mechanism is dependent on cellular metabolism and is markedly decreased by metabolic inhibitors or in the absence of a metabolizable hexose. Cycloheximide, which inhibits protein biosynthesis, also blocks the active transport. Perfusion of jejunal and duodenal intestinal loops in situ in anesthetized rats provides evidence that endogenous Fe can be transferred to the lumen by a process otherthan shedding of mucosal cells. It is suggested that such transfer may occur via the active transport mechanism.

Competition between Carnosine and other Peptides for Transport by Hamster Jejunum in Vitro

1974 ◽  
Vol 46 (6) ◽  
pp. 707-714 ◽  
Author(s):  
Jill M. Addison ◽  
D. M. Matthews ◽  
D. Burston
Keyword(s):  
Amino Acids ◽  
Intestinal Mucosa ◽  
Free Amino Acids ◽  
Free Amino ◽  
Common Mechanism ◽  
Uptake Mechanism ◽  
Mucosal Cells ◽  
Dipeptide Uptake

1. This paper reports the results of experiments on competition for transport by hamster jejunum in vitro between carnosine (β-alanyl-l-histidine) and other peptides and amino acids. Carnosine was chosen because this dipeptide is taken up intact with very little hydrolysis, which simplifies interpretation of the results. 2. Jejunal uptake of carnosine was inhibited by equimolar glycylglycine, glycylglycylglycine, glycylsarcosine, glycylproline, methionylmethionine and prolylhydroxy-proline but not by the equivalent free amino acids, or by a mixture of β-alanine and histidine. Inhibition of carnosine uptake by glycylproline was shown to be competitive. It is suggested that carnosine and the dipeptides inhibiting its uptake enter the mucosal cells by a common mechanism which is independent of the entry mechanisms for amino acids. Uptake of carnosine was not inhibited by N-acetylglycylglycine or by glycylglycine amide, suggesting that these substitutions prevent glycylglycine utilizing the dipeptide-uptake mechanism. 3. Carnosine uptake was not inhibited by equimolar lysyllysine or α-glutamylglutamic acid, nor did lysyllysine and α-glutamylglutamic acid affect uptake of each other. Though these results are compatible with the existence of multiple dipeptide-uptake systems in the intestinal mucosa, the evidence at present available is insufficient to permit any conclusion on this point.

In vitro Action of Gastric Mucosal Lysosomal Enzymes on Intracellular Gastric Glycoproteins

1979 ◽  
Vol 34 (1-2) ◽  
pp. 90-95 ◽  
Author(s):  
Fouad M. Fouad ◽  
D. Waldron-Edward
Keyword(s):  
Cell Wall ◽  
Lysosomal Enzymes ◽  
Gastric Ulceration ◽  
Mucosal Cell ◽  
Gastric Lesions ◽  
Acid Hydrolases ◽  
Gastric Mucosal Cells ◽  
Mucosal Cells ◽  
Specific Increase

Abstract The results show that incubation of gastric mucosal cells from rat at pH ~4.5 or in the presence of aspirin is associated with a specific increase in the activity of some acid-hydrolases. Intracellular glycoproteins, isolated by non-degradative techniques from rat or dog fundic mucosal cells, were found to be potential bio-substrates for these acid-hydrolyses. This may suggest that cleavage of the carbohydrate moieties of the intracellular and mucosal cell wall glycoproteins is a fundamental step in the development of gastric ulceration. A model for gastric lesions is proposed and discussed in the light of the results obtained.

scholarly journals Evaluation of a moisturising micro‐gel spray for prevention of cell dryness in oral mucosal cells: an in vitro study and evaluation in a clinical setting

2012 ◽  
Vol 21 (6) ◽  
pp. 728-734 ◽  
Author(s):  
Y. OTA ◽  
A. MORITO ◽  
K. FUJISAWA ◽  
M. NISHIDA ◽  
H. HATA ◽  
...  
Keyword(s):  
Clinical Setting ◽  
In Vitro Study ◽  
Vitro Study ◽  
Mucosal Cells

scholarly journals Phosphorylation and an ATP-dependent process increase the dynamic exchange of H1 in chromatin

2002 ◽  
Vol 158 (7) ◽  
pp. 1161-1170 ◽  
Author(s):  
Yali Dou ◽  
Josephine Bowen ◽  
Yifan Liu ◽  
Martin A. Gorovsky
Keyword(s):  
Negative Charge ◽  
Histone H1 ◽  
Linker Histone ◽  
Global Effect ◽  
Dynamic Binding ◽  
Linker Histone H1 ◽  
Dependent Process ◽  
Dynamic Exchange

In Tetrahymena cells, phosphorylation of linker histone H1 regulates transcription of specific genes. Phosphorylation acts by creating a localized negative charge patch and phenocopies the loss of H1 from chromatin, suggesting that it affects transcription by regulating the dissociation of H1 from chromatin. To test this hypothesis, we used FRAP of GFP-tagged H1 to analyze the effects of mutations that either eliminate or mimic phosphorylation on the binding of H1 to chromatin both in vivo and in vitro. We demonstrate that phosphorylation can increase the rate of dissociation of H1 from chromatin, providing a mechanism by which it can affect H1 function in vivo. We also demonstrate a previously undescribed ATP-dependent process that has a global effect on the dynamic binding of linker histone to chromatin.

In vitro absorption of bile salts by small intestine of rats and guinea pigs

1961 ◽  
Vol 200 (2) ◽  
pp. 313-317 ◽  
Author(s):  
Leon Lack ◽  
I. M. Weiner
Keyword(s):  
Small Intestine ◽  
Bile Acid ◽  
Active Transport ◽  
Sodium Azide ◽  
Concentration Gradient ◽  
Guinea Pigs ◽  
Bile Salts ◽  
Ileal Segment

The transport of taurocholic and glycocholic acids by the small intestine of rats and guinea pigs against a concentration gradient was studied by the everted gutsac technique. Transport of these substances is limited to the distal ileal segment. This transport is inhibited by anoxia, dinitrophenol and sodium azide. The system has a transport maximum. On the basis of these criteria bile acid reabsorption is considered to occur by active transport.

Sign in / Sign up

Export Citation Format

Share Document