Effect of theophylline on l-alanine absorption in the rat jejunum

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dc.contributor.author Daher, Costantine F.
dc.contributor.author Khoury, Carmen I.
dc.contributor.author Nassar, Camille
dc.date.accessioned 2015-12-16T07:32:21Z
dc.date.available 2015-12-16T07:32:21Z
dc.date.copyright 2004
dc.date.issued 2015-12-16
dc.identifier.issn 0278-6915 en_US
dc.identifier.uri http://hdl.handle.net/10725/2813
dc.description.abstract The effect of theophylline on the accumulation of l-alanine (Ala) by the rat jejunum and the mechanism involved has been investigated. Ala is rapidly accumulated by the jejunal strips in vitro and saturation is reached between 10 and 15 min. An In/Out ratio of 2.55 reflects the presence of an active component in the overall transport mechanism. Ala accumulation shows a tendency toward saturation as cellular Ala concentration increases. In the absence of Na+, Ala accumulation is reduced and a direct relationship is observed between alanine concentration in the incubation medium and its intracellular concentration. Alanine accumulation is inhibited when theophylline (TH) concentration in the incubation medium is greater than 0.5 mM. A maximum inhibition of approximately 50% in the presence of 10 mM theophylline is observed. Further inhibition (57–65%) is observed when the jejunal strips are incubated in a Na+-free medium containing 10 mM theophylline. Single-pass perfusion of the rat jejunum shows that the presence of 0.5 mM TH in the perfusate, simulating therapeutic doses, did not affect Ala absorption. However, about 55% inhibition of Ala absorption was observed when 10 mM TH was included in the perfusate. In conclusion, it could be stated that in both in vitro and in vivo studies high toxic but not therapeutic doses of TH inhibit intestinal Ala uptake. The mechanism of inhibition may be attributed to a non-carrier mediated mechanism with a minor effect noticed on Ala carrier system. en_US
dc.language.iso en en_US
dc.title Effect of theophylline on l-alanine absorption in the rat jejunum en_US
dc.type Article en_US
dc.description.version Published en_US
dc.author.school SAS en_US
dc.author.idnumber 199190130 en_US
dc.author.woa N/A en_US
dc.author.department Natural Sciences en_US
dc.description.embargo N/A en_US
dc.relation.journal Food and Chemical Toxicology en_US
dc.journal.volume 42 en_US
dc.journal.issue 12 en_US
dc.article.pages 1971-1976 en_US
dc.keywords l-alanine en_US
dc.keywords Absorption en_US
dc.keywords Intestine en_US
dc.keywords Theophylline en_US
dc.identifier.doi http://dx.doi.org/10.1016/j.fct.2004.07.012 en_US
dc.identifier.ctation Daher, C. F., Khoury, C. I., & Nassar, C. F. (2004). Effect of theophylline on L-alanine absorption in the rat jejunum. Food and chemical toxicology, 42(12), 1971-1976. en_US
dc.author.email cdaher@lau.edu.lb
dc.identifier.url http://www.sciencedirect.com/science/article/pii/S0278691504002212

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