Studies on the mechanism of the cortisol inhibition of hexose uptake in rat thymocytes in vitro and the effect of anaerobiosis and temperature on the expression of this inhibition.

1975 ◽  
Author(s):  
Lawrence Paul Zyskowski
Keyword(s):  
Hexose Uptake

Kinetics of hexose uptake by the small and large intestine of the chicken

1996 ◽  
Vol 271 (4) ◽  
pp. R1085-R1089 ◽  
Author(s):  
C. Amat ◽  
J. M. Planas ◽  
M. Moreto
Keyword(s):  
Large Intestine ◽  
Diffusion Constant ◽  
High Capacity ◽  
Minor Role ◽  
Passive Mechanism ◽  
Hexose Uptake ◽  
Kinetics Of ◽  
Distal Direction ◽  
Small And Large Intestine

The kinetic parameters of hexose uptake by the small and large intestine of the chicken have been determined in vitro. Rates of initial influx of alpha-methyl-D-glucoside and L-glucose were measured in everted sleeves of the duodenum, jejunum, ileum, proximal cecum, and rectum. Results show the following. 1) Maximal transport capacity values for alpha-methyl-D-glucoside show that the jejunum is the segment that is best suited for Na(+)-mediated uptake. 2) The calculated apparent Michaelis constant values were (in mmol/l) 11.6 for duodenum, 7.8 for jejunum, 3.5 for ileum, 2.4 for proximal cecum, and 7.1 for rectum. This suggests that, with the exception of the rectum, the affinity of the carrier for alpha-methyl-D-glucoside progressively increases in the distal direction. 3) Diffusion constant values indicate that influx of hexoses by a passive mechanism in the duodenum and proximal cecum is significantly higher than in the other segments. 4) The sum of passive and mediated mechanisms confers to the duodenum and jejunum a high capacity to absorb hexoses. The ileum, proximal cecum, and rectum have a quantitatively minor role, albeit significant, in completing the absorptive function.

The Basis of Osmotic Pressure Maintenance During Expansion Growth in Helianthus annuus Hypocotyls

1976 ◽  
Vol 3 (3) ◽  
pp. 311 ◽  
Author(s):  
DL Mcneil
Keyword(s):  
Osmotic Pressure ◽  
Accumulation Rate ◽  
Sucrose Concentration ◽  
Sugar Accumulation ◽  
Bathing Solution ◽  
Bathing Medium ◽  
Intact Tissue ◽  
Hexose Uptake

In etiolated sunflower (H. annuus) hypocotyls, the intracellular osmotic pressure was maintained in spite of the dilution caused by growth. The principal osmotic substances present were hexoses (44 � 6 mol m-3 glucose and 40 � 5 mol m-3 fructose) and organic potassium salts (30 mol m-3). , Potassium fluxes in vivo (intact rooted seedlings) and in vitro (1 cm, peeled, cut sections in an aerated bathing solution) were similar, indicating that the sectioning had not affected cell fluxes. The uptake of 3-O-methyl glucose by cut sections from a bathing medium was lower than the uptake estimated using intact tissue (in vitro influx was 5 % of the net accumulation rate of intact tissue). This suggested that some pathway of hexose uptake other than from the extracellular spaces occurred in vivo. To explain this difference in reducing sugar accumulation rates the following pathway is suggested: (1) Transport of sucrose from the cotyledons via the phloem; (2) Direct unloading of the sucrose into the symplast; (3) Transport of the sucrose into the vacuole down a sucrose concentration gradient maintained by hydrolysis of sucrose to glucose and fructose; (4) Low hexose efflux from the vacuole (5 % of in vivo influx), preventing loss from the vacuole.

Alternate models for shared carriers or a single maturing carrier in hexose uptake into rabbit jejunum in vitro

1987 ◽  
Vol 903 (1) ◽  
pp. 229-240 ◽  
Author(s):  
A.B.R. Thomson ◽  
M.L.G. Gardner ◽  
G.L. Atkins
Keyword(s):  
Rabbit Jejunum ◽  
Hexose Uptake

scholarly journals Development of hormone receptors and hormone responsiveness in vitro. Effect of prolonged insulin treatment on hexose uptake in 3T3-L1 adipocytes.

1978 ◽  
Vol 253 (20) ◽  
pp. 7579-7583 ◽  
Author(s):  
O.M. Rosen ◽  
C.J. Smith ◽  
C. Fung ◽  
C.S. Rubin
Keyword(s):  
Hormone Receptors ◽  
Insulin Treatment ◽  
Hexose Uptake ◽  
Vitro Effect ◽  
Hormone Responsiveness

Effect of glucocorticoids on hexose uptake by mouse fibroblasts in vitro

Biochemistry ◽  
1971 ◽  
Vol 10 (2) ◽  
pp. 277-284 ◽  
Author(s):  
William B. Pratt ◽  
Jean G. Gray ◽  
Lewis Aronow
Keyword(s):  
Mouse Fibroblasts ◽  
Hexose Uptake

Role of calcium ions in insulin action on hexose transport in L6 muscle cells

1984 ◽  
Vol 247 (3) ◽  
pp. E297-E304 ◽  
Author(s):  
A. Klip ◽  
G. Li ◽  
W. J. Logan
Keyword(s):  
Glucose Uptake ◽  
Insulin Action ◽  
Muscle Cells ◽  
Ionophore A23187 ◽  
Vitro Model ◽  
Hexose Uptake ◽  
Absolute Measurements ◽  
Free Media ◽  
Stimulation Of

It has been proposed that Ca2+ ions mediate the stimulation by insulin of glucose uptake in muscle (Clausen, T., Cell Calcium 1:311–325, 1980). However, absolute measurements of the concentration of cytosolic free Ca2+, [Ca2+]i, during the course of insulin action have not been made. The stimulation of hexose uptake by insulin was studied in an in vitro model system of muscle cells, the L6 cell line. The following evidence suggests that Ca2+ ions are not likely to fulfill the purported role. 1) Insulin in Ca2+-free media induced stimulation of 2-deoxy-D-glucose uptake. 2) Elevation of [Ca2+]i with the ionophore A23187 did not enhance hexose uptake. 3) Insulin action was not diminished when the hormone was added to Ca2+-depleted cells in Ca2+-free media with A23187. 4) Hexose uptake was not affected by a number of agents thought to modify [Ca2+]i including epinephrine, caffeine, 2,4-dinitrophenol, hyperosmolar mannitol, salicylate, vanadate, veratrine, and trypsin. 5) Direct determinations of [Ca2+]i by fluorescence of the novel indicator Quin-2 did not show differences between basal and insulin-stimulated cells; under identical conditions hexose uptake was stimulated by the hormone. 6) Chelation of [Ca2+]i with Quin-2 in Ca2+-free media did not affect the response to insulin. 7) Low concentrations of trypsin (7.5 micrograms/ml) elevated [Ca2+]i but did not increase the rate of hexose uptake.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

In Vitro Induction of Crystals of MT Protein by Vinblastine-Colcemid in Mouse Spermatids

1974 ◽  
Vol 32 ◽  
pp. 132-133
Author(s):  
John J. Wolosewick ◽  
John H. D. Bryan
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Nuclear Ring ◽  
Rough Er ◽  
Distal Direction ◽  
In Vitro Induction

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

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