title: Possible role of PEPT1 in gastrointestinal hormone secretion.
abstract: Oligopeptides originating from ingested meal stimulate the secretion of various gastrointestinal hormones, but the mechanism is unknown. In this study, we show that transfection of oligopeptide transporter 1 (PEPT1) in STC-1 cells, a murine enteroendocrine cell line, evokes di-peptide-stimulated hormone secretion in a pH-dependent manner. Measurement of membrane potentials shows that PEPT1- transfected STC-1 cells are depolarized by di-peptide glycyl-glycine but not by glycine monomer. Glycyl-glycine stimulation induces a rise in the intracellular calcium concentration in PEPT1-transfected STC-1 cells. The secretion induced by glycyl-glycine in PEPT1-transfected STC-1 cells was blocked by nifedipine, a Ca(2+) channel blocker, suggesting that the secretion is triggered by Ca(2+) influx through L-type voltage-dependent Ca(2+) channels. These data suggest that PEPT1 mediates oligopeptide-induced hormone secretion in enteroendocrine cells.
authors.affiliation: Division of Cellular and Molecular Medicine, Kobe University Graduate School of Medicine, Japan.
authors.forename: Kimio
authors.initials: K
authors.lastname: Matsumura
authors.forename: Takashi
authors.initials: T
authors.lastname: Miki
authors.forename: Takahito
authors.initials: T
authors.lastname: Jhomori
authors.forename: Tohru
authors.initials: T
authors.lastname: Gonoi
authors.forename: Susumu
authors.initials: S
authors.lastname: Seino
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000502:physiology; D002460:Cell Line; D019858:Enteroendocrine Cells / Q000187:drug effects / Q000502:physiology*; D005998:Glycine / Q000494:pharmacology; D006033:Glycylglycine / Q000494:pharmacology; D019382:Human Growth Hormone / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007424:Intracellular Fluid / Q000378:metabolism; D008564:Membrane Potentials; D051379:Mice; D009543:Nifedipine / Q000494:pharmacology; D000074011:Peptide Transporter 1; D011994:Recombinant Proteins / Q000378:metabolism; D027981:Symporters / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D000074011:Peptide Transporter 1; D011994:Recombinant Proteins; C082186:SLC15A1 protein, human; D027981:Symporters; D006033:Glycylglycine; D019382:Human Growth Hormone; D009543:Nifedipine; D002118:Calcium; D005998:Glycine