Metabolism of ε-(γ-L-glutamyl)-L-lysine in the rat

1. A study was made of the metabolism of ɛ-(γ-L-glutamyl)-L[4, 5-3H]lysine (GL) in the rat.2. The compound was largely absorbed from the intestine and metabolized. Labelled lysine was incorporated into blood proteins.3. In an in vitro experiment with everted sacs of rat small intestine, GL passed through the intestinal wall unchanged.4. The results of comparative tests using homogenates of different body tissues indicated that the kidneys were particularly active in hydrolysing GL. Their activity was nine times greater than that of the liver and eighteen times greater than that of the small intestine.

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A comparison of the structural integrity of several commonly used preparations of rat small intestine in vitro

Clinical Science ◽

10.1042/cs0730053 ◽

1987 ◽

Vol 73 (1) ◽

pp. 53-59 ◽

Cited By ~ 19

Author(s):

Jane A. Plumb ◽

David Burston ◽

Terry G. Baker ◽

Michael L. G. Gardner

Keyword(s):

Small Intestine ◽

Structural Integrity ◽

Transport Processes ◽

Buffer System ◽

Rat Small Intestine ◽

Quantitative Studies ◽

Routine Monitoring ◽

Anaesthetized Rats ◽

Everted Sacs

1. The structural integrities of various preparations of rat small intestine for the study of absorption in vitro have been compared after incubation or perfusion. 2. Perfused intestines removed from anaesthetized rats, and thus never deprived of a supply of oxygen, maintain their structural integrity even after perfusion for 1 h provided that a Krebs–Henseleit bicarbonate perfusate is used. However, intestines removed from freshly killed rats show severe villus disruption and oedema after perfusion for only 20 min. 3. Extensive damage to both crypts and villi is observed in everted sacs of small intestine incubated for 20 min, regardless of the buffer system used. Intestinal rings show damage at the tips of the villi after incubation for 2 min, but otherwise remain morphologically intact; this damage is progressive with time. 4. It is concluded that the exact mode of preparation of intestinal tissue is critical for preservation of structural and functional integrity and that this is especially important in quantitative studies on transport processes. Further, it is recommended that routine monitoring of the integrity of intestinal preparations in vitro is desirable and that histological assessment is an appropriate technique.

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Steady-state metabolism and transport of d-glucose by rat small intestine in vitro

Biochemical Journal ◽

10.1042/bj1640001a ◽

1977 ◽

Vol 164 (1) ◽

pp. 1-14 ◽

Cited By ~ 22

Author(s):

Penelope J. Pritchard ◽

John W. Porteous

Keyword(s):

Small Intestine ◽

Steady State ◽

Incubation Medium ◽

Physiological State ◽

Ionic Composition ◽

Rat Small Intestine ◽

Mucosal Tissue ◽

Experimental Conditions ◽

Everted Sacs

1. Conditions of incubation of everted sacs of rat small intestine were selected to ensure that absorption of d-glucose by mucosal tissue from the incubation medium, intracellular metabolism of the absorbed glucose and transport of glucose through the intact intestinal tissue proceeded linearly with respect to time of incubation within stated time intervals. 2. Under these experimental conditions, steady intracellular concentrations of glucose and lactate were demonstrated. 3. The quantitative translocational and metabolic fate of absorbed glucose was determined under these steady-state conditions. About 25% of glucose absorbed from the external mucosal solution was accumulated (temporarily) within mucosal tissue and about 25% transported through the intact tissue into the external serosal solution; the remainder (about 50%) of the absorbed glucose was metabolized, 90% to lactate and 10% to CO2. Concomitant respiration rates were comparable with those reported for several other preparations of intestine and were stoicheiometrically in excess of the O2 metabolism required to account for the production of CO2 from the absorbed glucose. 4. Water transport through the everted sacs proceeded at an optimum rate under the experimental conditions selected. 5. Some other observations are recorded which influenced the design of the experiments and the interpretation of results; these include the initial physiological state of the animal, the anaesthetic used and the ionic composition of the incubation medium.

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In Silico and in Vitro Evaluation of Deamidation Effects on the Stability of the Fusion Toxin DAB389IL-2

Current Proteomics ◽

10.2174/1570164616666190131150033 ◽

2019 ◽

Vol 16 (4) ◽

pp. 307-313 ◽

Cited By ~ 2

Author(s):

Nasrin Zarkar ◽

Mohammad Ali Nasiri Khalili ◽

Fathollah Ahmadpour ◽

Sirus Khodadadi ◽

Mehdi Zeinoddini

Keyword(s):

In Silico ◽

Catalytic Domain ◽

Md Simulations ◽

Special Importance ◽

Native Form ◽

Vitro Experiment ◽

In Vitro Experiment ◽

Pharmaceutical Protein ◽

The Stability

Background: DAB389IL-2 (Denileukin diftitox) as an immunotoxin is a targeted pharmaceutical protein and is the first immunotoxin approved by FDA. It is used for the treatment of various kinds of cancer such as CTCL lymphoma, melanoma, and Leukemia but among all of these, treatment of CTCL has special importance. DAB389IL-2 consists of two distinct parts; the catalytic domain of Diphtheria Toxin (DT) that genetically fused to the whole IL-2. Deamidation is the most important reaction for chemical instability of proteins occurs during manufacture and storage. Deamidation of asparagine residues occurs at a higher rate than glutamine residues. The structure of proteins, temperature and pH are the most important factors that influence the rate of deamidation. Methods: Since there is not any information about deamidation of DAB389IL-2, we studied in silico deamidation by Molecular Dynamic (MD) simulations using GROMACS software. The 3D model of fusion protein DAB389IL-2 was used as a template for deamidation. Then, the stability of deamidated and native form of the drug was calculated. Results: The results of MD simulations were showed that the deamidated form of DAB389IL-2 is more unstable than the normal form. Also, deamidation was carried by incubating DAB389IL-2, 0.3 mg/ml in ammonium hydrogen carbonate for 24 h at 37o C in order to in vitro experiment. Conclusion: The results of in vitro experiment were confirmed outcomes of in silico study. In silico and in vitro experiments were demonstrated that DAB389IL-2 is unstable in deamidated form.

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Absorption of lactulose from mammalian gastrointestinal tract

British Journal Of Nutrition ◽

10.1079/bjn19790010 ◽

1979 ◽

Vol 41 (1) ◽

pp. 47-51 ◽

Cited By ~ 8

Author(s):

D. F. Evered ◽

F. Sadoogh-Abasian

Keyword(s):

Small Intestine ◽

Calcium Ions ◽

Clinical Evidence ◽

Buccal Cavity ◽

Rat Small Intestine ◽

Sodium Ions ◽

Mode Of Transport ◽

Poor Absorption

1. The disaccharide lactulose (galactosyl-β-1,4-fructose) was poorly absorbed from rat small intestine in vitro and human mouth in vivo.2. These results confirm indirect clinical evidence of poor absorption from the intestine.3. The presence of calcium ions, or absence of sodium ions, had no effect on lactulose absorption from the buccal cavity.4. The presence of ouabain, or absence of Na+, did not decrease the absorption of lactulose from small intestine.5. It is thought that the mode of transport, in both instances, is by passive diffusion with the concentration gradient.

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