Analysis of segmental phosphate absorption in intact rats. A compartmental analysis approach
| Autor: | D. B. N. Lee, Ming Shu Hu, N. Jamgotchian, L. H. Kayne, J. H. Meyer, David Z. D'Argenio |
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| Rok vydání: | 1993 |
| Předmět: |
Male
Colon Stereochemistry Kinetics Polyethylene glycol Models Biological Intestinal absorption Phosphates Polyethylene Glycols Rats Sprague-Dawley chemistry.chemical_compound In vivo Intestine Small PEG ratio medicine Pi Animals Carbon Radioisotopes Gastrointestinal tract Chromatography Stomach digestive oral and skin physiology General Medicine Rats medicine.anatomical_structure Intestinal Absorption chemistry Organ Specificity Duodenum Calcium Phosphorus Radioisotopes Research Article |
| Zdroj: | Journal of Clinical Investigation. 91:915-922 |
| ISSN: | 0021-9738 |
| DOI: | 10.1172/jci116313 |
| Popis: | Available information supports the dominance of the proximal intestine in inorganic phosphate (Pi) absorption. However, there is no strategy for analyzing segmental Pi absorption from a spontaneously propelled meal in an intact animal. We propose a solution using compartmental analysis. After intragastric administration of a 32P-labeled Pi liquid meal containing a nonabsorbable marker, [14C]polyethylene glycol (PEG), rats were killed at 2, 10, 20, 30, 60, 120, and 240 min. The gastrointestinal tract was removed and divided into seven segments, from which 32P and [14C]PEG were recovered. Data was expressed as a percentage of the dose fed, i.e., (32P[in segment] divided by 32P[fed]) and [14C]PEG[in segment] divided by [14C]PEG[fed]), respectively. A compartmental model was constructed and the rate constants for intersegmental transit and segmental absorption were estimated. The "goodness of fit" between the simulated model and the actual data indicates the estimated rate constants reflect in vivo events. The duodenum, with the highest transit and absorption rates, accounted for a third of the total absorption. However, the terminal ileum, with a lower absorption rate but a longer transit time, absorbed an equal amount of Pi. This approach allows the analysis of the mechanism and the regulation of Pi absorption under more authentic in vivo conditions. |
| Databáze: | OpenAIRE |
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