Linked Life Data

9649359

Source:http://linkedlifedata.com/resource/pubmed/id/9649359

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1998-8-5
pubmed:abstractText
The purpose of this study was to determine the intestinal absorption characteristics of AG337, a mechanism-based inhibitor of thymidylate synthase, using a perfused rat intestinal model. Effects of site, pH, temperature, concentration, Na+, and inhibitors on the absorption of AG337 were determined, after the compound was shown to be stable in buffers of various pH, blank perfusate, and intestinal homogenate. The results indicated that absorption of AG337 was temperature-, pH-, Na+-, concentration-, and site-dependent. The best site of absorption is duodenum, where the absorption was 3-10 times (p < 0. 05) higher than absorption at jejunum, ileum, and colon. Among the four pH's studied, the best was at pH 6.5 (p < 0.05). Absorption was 80% lower in the absence of Na+, and 75% lower when the temperature of the perfusate was decreased to 4 degreesC. Permeability of AG337 also decreased about 75% when the concentration was raised to 100 microM. These results suggest that a nutrient carrier may be involved in the transport of AG337. To determine the carrier responsible for the absorption of AG337, its absorption was determined in the presence of various inhibitors at different concentrations. The results indicated that transport of AG337 was inhibited significantly (p < 0.01) by 100 microM of adenine, hypoxanthine, and xanthine. The transport was also inhibited significantly (p < 0.01) by a mixture of 100 microM each of adenine, hypoxanthine, and xanthine, but not by a mixture of 100 microM each of thymine and uracil. A higher concentration of hypoxanthine resulted in increased inhibition. In contrast, prototypical inhibitors of nucleoside transporter, dipyridamole and nitrobenzylthioinosine (NBMPR), did not significantly decrease the transport of AG337. The results also showed that absorption of AG337 had a significant nonsaturable component, with a nonsaturable Pw of 0.8. In conclusion, absorption of AG337 in the rat intestine has been shown to be mainly via a purine base carrier with a significant nonsaturable component.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-3549
pubmed:author
pubmed:issnType
Print
pubmed:volume
87
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
886-90
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:9649359-Animals, pubmed-meshheading:9649359-Biological Transport, pubmed-meshheading:9649359-Cell Membrane Permeability, pubmed-meshheading:9649359-Drug Stability, pubmed-meshheading:9649359-Duodenum, pubmed-meshheading:9649359-Enzyme Inhibitors, pubmed-meshheading:9649359-Hydrogen-Ion Concentration, pubmed-meshheading:9649359-Ileum, pubmed-meshheading:9649359-Intestinal Absorption, pubmed-meshheading:9649359-Jejunum, pubmed-meshheading:9649359-Male, pubmed-meshheading:9649359-Nucleosides, pubmed-meshheading:9649359-Perfusion, pubmed-meshheading:9649359-Purines, pubmed-meshheading:9649359-Quinazolines, pubmed-meshheading:9649359-Rats, pubmed-meshheading:9649359-Rats, Sprague-Dawley, pubmed-meshheading:9649359-Sodium, pubmed-meshheading:9649359-Temperature, pubmed-meshheading:9649359-Thymidylate Synthase
pubmed:year
1998
pubmed:articleTitle
Determination of absorption characteristics of AG337, a novel thymidylate synthase inhibitor, using a perfused rat intestinal model.
pubmed:affiliation
Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Pullman, Washington 99164-6510, USA. minghu@wsu.edu
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't