Intestinal absorption pathway of gamma-aminobutyric acid in rat small intestine
| Autor: | M. Merino, Amparo Nácher, Ana Polache, J.M. Plá-Delfina, M J Moll-Navarro |
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| Rok vydání: | 1994 |
| Předmět: |
Absorption (pharmacology)
Male Pharmaceutical Science Michaelis–Menten kinetics Aminobutyric acid Intestinal absorption Diffusion Non-competitive inhibition Body Water In vivo Intestine Small medicine Animals Pharmacology (medical) Rats Wistar Chromatography High Pressure Liquid gamma-Aminobutyric Acid Pharmacology Alanine Chemistry General Medicine Membrane transport Small intestine Rats medicine.anatomical_structure Spectrometry Fluorescence Biochemistry Intestinal Absorption Biophysics |
| Zdroj: | Biopharmaceuticsdrug disposition. 15(5) |
| ISSN: | 0142-2782 |
| Popis: | Intestinal absorption of gamma-aminobutyric acid (GABA), as a model compound for gamma-aminoacids, has not been extensively studied from the kinetic viewpoint. Since data from our laboratory suggested that some competition arises between intestinal absorption of beta-alanine and GABA and since our intent was to maintain the aqueous stagnant diffusion layer in order to approach absorption tests to in vivo physiological conditions, a rat jejunum in situ study was undertaken in order to gain an insight into the mechanism of GABA absorption. In the present paper, results from assays using isotonic perfusion solutions with starting GABA concentrations ranging from 1 to 50 mM are reported. They show that the intestinal absorption of the gamma-aminoacid can be apparently described as a specialized transport mechanism which obeys Michaelis-Menten and first-order kinetics. Parameter values found were Vm = 13.99 +/- 2.37 mM h-1, Km = 3.87 +/- 0.63 mM, and ka(passive) = 0.362 +/- 0.120 h-1. Through the perfusion of 5 mM beta-alanine solutions containing variable concentrations of GABA (from 5 to 50 mM), a partially competitive inhibition of beta-alanine absorption was apparently characterized. |
| Databáze: | OpenAIRE |
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