Macromolecular transport across the rabbit proximal and distal colon
| Autor: | D. G. Gall, James A. Hardin, M Wirasinghe, M H Kimm |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1999 |
| Předmět: |
Male
Colon Macromolecular Substances Serum albumin Tetrodotoxin Intestinal absorption chemistry.chemical_compound Intestinal mucosa Culture Techniques Sodium fluoride medicine Animals Large intestine Bovine serum albumin Intestinal Mucosa Lagomorpha biology Dose-Response Relationship Drug Gastroenterology Biological Transport Serum Albumin Bovine biology.organism_classification Small intestine medicine.anatomical_structure Biochemistry chemistry Intestinal Absorption biology.protein Biophysics Sodium Fluoride Female Rabbits Colchicine |
| Popis: | BackgroundAlthough many studies have investigated macromolecular uptake in the stomach and small intestine, little is known about macromolecular uptake in the colon.AimsTo investigate the mechanisms involved in the transport of large antigenically intact macromolecules across the proximal and distal colonic epithelium in the rabbit.MethodsThe mucosal to serosal movement of bovine serum albumin (BSA) was examined in modified Ussing chambers under short circuited conditions. The mucosal surface was exposed to varying concentrations of BSA, and after a 50 minute equilibration period, the mucosal to serosal flux of immunologically intact BSA was determined by ELISA. Total BSA flux was determined by the transport of radiolabelled 125I-BSA.ResultsIntact BSA transport in proximal and distal colonic tissue showed saturable kinetics. Intact BSA transport in the proximal and distal segment was 7% and 2% of the total 125I-BSA flux respectively. Immunologically intact BSA transport in the distal segment was significantly less than that in the proximal segment. Intact BSA transport in the proximal colon was significantly reduced following treatment with sodium fluoride, colchicine, and tetrodotoxin. Cholinergic blockade had no effect on the uptake of intact BSA.ConclusionThe findings indicate that the transport of intact macromolecules across the proximal and distal large intestine is a saturable process. Further, intact BSA transport in the proximal colon is an energy dependent process that utilises microtubules and is regulated by the enteric nervous system. |
| Databáze: | OpenAIRE |
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