Effects of short chain fatty acids on colonic Na+ absorption and enzyme activity
| Autor: | Richard W. Egnor, Elliot Newman, Alan N. Charney, Manuela Varzescu, Ibrahim Djavadi, Valentin Zaharia, Jesline Alexander-Chacko |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
medicine.medical_specialty
Colon Physiology Butyrate digestive system Biochemistry Adenylyl cyclase chemistry.chemical_compound Chlorides Carbonic anhydrase Internal medicine Cyclic AMP medicine Animals Humans Molecular Biology Carbonic Anhydrases chemistry.chemical_classification biology Ussing chamber Phosphoric Diester Hydrolases Fatty Acids Sodium digestive oral and skin physiology food and beverages Phosphodiesterase Metabolism digestive system diseases Enzyme assay Rats Endocrinology Enzyme Intestinal Absorption chemistry Guanylate Cyclase biology.protein lipids (amino acids peptides and proteins) Sodium-Potassium-Exchanging ATPase Adenylyl Cyclases |
| Zdroj: | Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 128:335-347 |
| ISSN: | 1095-6433 |
| DOI: | 10.1016/s1095-6433(00)00318-4 |
| Popis: | Short chain fatty acids (SCFA) stimulate colonic Na+ absorption and inhibit cAMP and cGMP-mediated Cl- secretion. It is uncertain whether SCFA have equivalent effects on absorption and whether SCFA inhibition of Cl- secretion involves effects on mucosal enzymes. Unidirectional Na+ fluxes were measured across stripped colonic segments in the Ussing chamber. Enzyme activity was measured in cell fractions of scraped colonic mucosa. Mucosal 50 mM acetate, propionate, butyrate and poorly metabolized isobutyrate stimulated proximal colon Na+ absorption equally (300%). Neither 2-bromo-octanoate, an inhibitor of beta-oxidation, nor carbonic anhydrase inhibition affected this stimulation. All SCFA except acetate stimulated distal colon Na+ absorption 200%. Only one SCFA affected proximal colon cGMP phosphodiesterase (PDE) (18% inhibition by 50 mM butyrate). All SCFA at 50 mM stimulated distal colon cAMP PDE (24-43%) and decreased forskolin-stimulated mucosal cAMP content. None of the SCFA affected forskolin-stimulated adenylyl cyclase in distal colon or ST(a)-stimulated guanylyl cyclase in proximal colon. Na+-K+-ATPase in distal colon was inhibited 23-51% by the SCFA at 50 mM. We conclude that all SCFA (except acetate in distal colon) stimulate colonic Na+ absorption equally, and the mechanism does not involve mucosal SCFA metabolism or carbonic anhydrase. SCFA inhibition of cAMP-mediated secretion may involve SCFA stimulation of PDE and inhibition of Na+-K+-ATPase. |
| Databáze: | OpenAIRE |
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