Diurnal Expression and Function of Peptide Transporter 1 (PEPT1)1

Hisham G. Qandeel, Judith A. Duenes, Ye Zheng, Michael G. Sarr

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Background: Protein is absorbed primarily as di/tripeptides, which are transported into the enterocyte exclusively by H+/peptide cotransporter 1 (PEPT1). Diurnal changes in expression and function of several other mucosal transporters occur in rat. Diurnal variations in mRNA, protein, and transport function of PEPT1 occur in rat duodenum and jejunum, but not in ileum. Methods: Mucosal levels of mRNA and protein were determined at 9 AM, 3 PM, 9 PM, and 3 AM (n = 6 each) by real time RT-PCR and Western blotting, respectively, in rats maintained in a 12-h light/dark room [light 6 AM to 6 PM]; transporter-mediated uptake of dipeptide (Gly-Sar) was also measured by everted sleeve technique. Results: mRNA transcripts of PEPT1 and Gly-Sar uptake varied diurnally in duodenum and jejunum (peak at 3 PM, P < 0.05), but not in ileum; maximal uptake was in jejunum. Vmax (nmol/cm/min) was greater at 3 PM and 9 PM compared with 9 AM (3 PM versus 9 AM: 104 versus 62 in duodenum, and 185 versus 101 in jejunum; P < 0.03); Km was unchanged across time points or locations. Protein levels varied minimally in jejunum and ileum with peaks at 9 PM and 3 AM. Conclusion: Gene expression and transport function of PEPT1 vary diurnally in duodenum and jejunum in temporal association with nocturnal feeding of rats.

Original languageEnglish (US)
Pages (from-to)123-128
Number of pages6
JournalJournal of Surgical Research
Volume156
Issue number1
DOIs
StatePublished - Sep 2009

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Jejunum
Duodenum
Ileum
Messenger RNA
Light
Proteins
Enterocytes
Dipeptides
Protein Transport
peptide permease
Real-Time Polymerase Chain Reaction
Western Blotting
Gene Expression
Peptides

Keywords

  • diurnal rhythm
  • PEPT1
  • peptide transporter 1
  • protein absorption
  • rat
  • short peptides
  • small intestine

ASJC Scopus subject areas

  • Surgery

Cite this

Diurnal Expression and Function of Peptide Transporter 1 (PEPT1)1 . / Qandeel, Hisham G.; Duenes, Judith A.; Zheng, Ye; Sarr, Michael G.

In: Journal of Surgical Research, Vol. 156, No. 1, 09.2009, p. 123-128.

Research output: Contribution to journalArticle

Qandeel, Hisham G. ; Duenes, Judith A. ; Zheng, Ye ; Sarr, Michael G. / Diurnal Expression and Function of Peptide Transporter 1 (PEPT1)1 In: Journal of Surgical Research. 2009 ; Vol. 156, No. 1. pp. 123-128.
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