Possible role of PEPT1 in gastrointestinal hormone secretion.
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.
Matsumura
Kimio
K
Division of Cellular and Molecular Medicine, Kobe University Graduate School of Medicine, Japan.
Miki
Takashi
T
Jhomori
Takahito
T
Gonoi
Tohru
T
Seino
Susumu
S
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
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