The ontogenetic development of PepT1, NBAT and EAAC1 along the vertical and horizontal axes of the rat small intestine was evaluated using semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. The proximodistal profiles of mRNA levels showed that PepT1 was evenly distributed, whereas NBAT had greater expression in the proximal part, and EAAC1 in the distal part. These regionalizations were the same from postnatal days 4 to 50. PepT1 and NBAT proteins were detected in the microvilli of enterocytes along the length of the villi. NBAT was also found in the cytoplasm. Surprisingly, EAAC1 was located exclusively in the microvilli of enterocytes in the crypt and the bases of the villi. These protein expression patterns were similar in all parts of the small intestine (proximal, median and distal), at all ages. We conclude that the expression of PepT1, NBAT or EAAC1 are differently regulated according to both the horizontal and vertical axes.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1093/jn/132.5.1009 | DOI Listing |
Comp Biochem Physiol B Biochem Mol Biol
January 2007
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
End products of digestion are absorbed by the body through the action of transporter proteins expressed on the apical membrane of intestinal epithelial cells. We investigated the mRNA abundance and distribution of a peptide transporter (PepT1), a glucose transporter (SGLT1), two amino acid transporters (NBAT and b(o,+)AT), and a digestive enzyme, aminopeptidase N (APN), in the intestinal tract of black bears (Ursus americanus). Intestinal total RNA was isolated from 10 bears and abundance of PepT1, SGLT1, NBAT, b(o,+)AT, and APN mRNA were determined by Northern blots.
View Article and Find Full Text PDFJ Nutr
November 2004
Institute for Cell and Molecular Biosciences, University of Newcastle Medical School, Newcastle upon Tyne, UK.
Intestinal function depends on the presence of luminal nutrients and is altered during starvation and refeeding. Amino acids are essential for enterocytes, but the luminal supply is compromised with changes in dietary intake. To test the hypothesis that during periods of restricted luminal nutrient availability mucosal cells undergo adaptations aimed toward preserving amino acid supply, the expression of amino acid and peptide transporter mRNAs was quantified in rats with no oral intake, whose nutritional status was maintained with total parenteral nutrition (TPN).
View Article and Find Full Text PDFJ Nutr
May 2002
UMR 914, Physiologie de la Nutrition et du Comportement Alimentaire, Institut National Agronomique Paris-Grignon, Paris, France.
The ontogenetic development of PepT1, NBAT and EAAC1 along the vertical and horizontal axes of the rat small intestine was evaluated using semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. The proximodistal profiles of mRNA levels showed that PepT1 was evenly distributed, whereas NBAT had greater expression in the proximal part, and EAAC1 in the distal part. These regionalizations were the same from postnatal days 4 to 50.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!