Intestinal absorption of cyclic phenylalanylserine (cyclo(Phe-Ser)), a precursor of gliotoxin, was studied in isolated rat small intestine as a model cyclic dipeptide. Absorption clearance (CLabs) decreased in the presence of glycylsarcosine, cephalexin or cephradine, substrates for H+/oligopeptide cotransporter (PEPT1). CLabs of cyclo(Phe-Ser) also decreased at 4 degrees C. These indicate that cyclo(Phe-Ser) is in part transported by PEPT1. However, Eadie-Hofstee plot of absorption revealed an atypical profile at lower concentrations of cyclo(Phe-Ser) (around 0.1 mM). Moreover, comparative experiments of absorptive and excretive transport showed that excretive transport from the serosal to mucosal side of isolated intestinal tissue at a 0.1 mM cyclo(Phe-Ser) was superior to absorptive transport from the mucosal side to the serosal side, and vise versa at a 1 mM cyclo(Phe-Ser). These results as well as the results of kinetic analysis indicate that intestinal absorption consists of passive transport, carrier-mediated absorptive transport by PEPT1 and carrier-mediated excretive transport, resulting in atypical absorption. Although cyclic dipeptides have potentials for drug, their intestinal absorption may be complex. The results of this study lead us conclude that absorptive and excretive transport by the small intestine acts as an interface between the body and ingested compounds.
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J Clin Biochem Nutr
January 2024
Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi 466-8550, Japan.
Mammalian cells contain thousands of metalloproteins and evolved systems to correctly incorporate metal cofactors into their designated sites. Among the transient metals in living cells, iron is the most abundant element that present as an iron sulfur cluster, mono- and dinuclear iron centers or heme for catalytic reactions. Iron homeostasis is tightly regulated by intestinal iron absorption in mammals owing to the lack of an iron excretive transport system, apart from superficial epithelial cell detachment and urinary outflow reabsorptive impairment.
View Article and Find Full Text PDFRSC Adv
October 2018
Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine Shanghai 201203 China
The Caco-2 cell monolayer model is widely utilized to predict drug permeability across human intestinal epithelial cells. However, at least 21 days is required for the formation and maturation of a well-tight Caco-2 cell monolayer, thereby restricting the throughput of the screening model during drug discovery. To address this challenge, a fast (7 days), and more physiologically relevant screening model integrating both the Caco-2 cell model and a small intestinal submucosa (SIS) hydrogel was developed in this study.
View Article and Find Full Text PDFRes Commun Mol Pathol Pharmacol
August 2004
Department of Biopharmaceutics and Drug Rational Research Center School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
Intestinal absorption of cyclic phenylalanylserine (cyclo(Phe-Ser)), a precursor of gliotoxin, was studied in isolated rat small intestine as a model cyclic dipeptide. Absorption clearance (CLabs) decreased in the presence of glycylsarcosine, cephalexin or cephradine, substrates for H+/oligopeptide cotransporter (PEPT1). CLabs of cyclo(Phe-Ser) also decreased at 4 degrees C.
View Article and Find Full Text PDFBiol Pharm Bull
November 2003
Department of Biopharmaceutics and Drug Rationale Research Center, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Horinouchi, Hachioji, Tokyo, Japan.
Intestinal absorption of peptides in linear form has been studied extensively, but there is little knowledge of peptides in a cyclic form. In this report, intestinal absorption of cyclic phenylalanylserine (cyclo(Phe-Ser)), a precursor of gliotoxin, was studied in isolated rat small intestine as a model cyclic dipeptide. Absorption clearance (CLabs) decreased in the presence of glycylsarcosine, cephalexin or cephradine, substrates for H+/oligopeptide cotransporter (PEPT1).
View Article and Find Full Text PDFJ Gen Appl Microbiol
February 1999
Department of Fermentation Technology, Faculty of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan.
To establish the molecular bases for development of a microbiological system approaching excretive fermentation of useful lipids, a mutant strain that accumulates lipids in the medium was isolated from the laboratory yeast Saccharomyces cerevisiae. Following the mutagenesis to strain YP1, a long chain fatty acid utilizer with ethylmethane sulfonate, the mutant strain, STG1, was selected from about 80,000 colonies. The analysis of extracellular lipids and the monitoring of leakage of intracellular proteins indicated that strain STG1 secreted lipids containing triacylglycerols into the extracellular space without cell lysis.
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