Unique mechanism of inhibition of Na+-amino acid cotransport during chronic ileal inflammation
| Autor: | Uma Sundaram, Sheik Wisel, John J. Fromkes |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Amino Acid Transport Systems
Transcription Genetic Physiology Ileum Biology Polymerase Chain Reaction digestive system Mediator Intestinal mucosa Physiology (medical) medicine Animals RNA Messenger Intestinal Mucosa Na+/K+-ATPase Ileal Diseases Inflammation chemistry.chemical_classification Alanine Microvilli Symporters Hepatology Coccidiosis Sodium Gastroenterology Biological Transport Cell biology Amino acid Kinetics Amino Acid Transport Systems Neutral medicine.anatomical_structure Biochemistry chemistry Chronic Disease Symporter Eimeria Rabbits Carrier Proteins Cotransporter |
| Zdroj: | American Journal of Physiology-Gastrointestinal and Liver Physiology. 275:G483-G489 |
| ISSN: | 1522-1547 0193-1857 |
| DOI: | 10.1152/ajpgi.1998.275.3.g483 |
| Popis: | In the chronically inflamed ileum, unique mechanisms of alteration of transport processes suggest regulation by different immune-inflammatory mediator pathways. We previously demonstrated that Na+-glucose cotransport in the chronically inflamed ileum was inhibited by a decrease in cotransporter number without a change in glucose affinity. The aim of this study was to determine the alterations in Na+-amino acid cotransport in chronically inflamed ileum produced by coccidial infection in rabbits. [3H]alanine uptake was performed in cells and vesicles by rapid filtration. In villus cells from chronically inflamed ileum, Na+-K+-ATPase was reduced 50% and Na+-alanine cotransport was also reduced (5.8 ± 1.2 in normal and 1.4 ± 0.5 nmol/mg protein in inflamed; n = 6, P < 0.05). [3H]alanine uptake in brush-border membrane vesicles was reduced in chronically inflamed ileum (73.2 ± 1.2 in normal and 21.5 ± 3.2 pmol/mg protein in inflamed; n = 3, P < 0.05), suggesting a direct effect on the cotransporter itself. Na+-amino acid cotransport in chronically inflamed ileum was inhibited by a decrease in affinity without a change in the maximal rate of uptake, and unaltered steady-state mRNA levels also suggested that the number of cotransporters was unchanged. Thus the mechanisms of inhibition of Na+-amino acid cotransport and Na+-glucose cotransport in chronically inflamed ileum are different. These observations suggest that different immune-inflammatory mediators may regulate different transport pathways during chronic ileitis. |
| Databáze: | OpenAIRE |
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