title: Leukotrienes stimulate pepsinogen secretion from guinea pig gastric chief cells by a nitric oxide-dependent pathway.
abstract: OBJECTIVE
  Leukotrienes (LTs) are involved in many inflammatory conditions including gastric damage induced by nonsteroidal anti-inflammatory drugs. Although LTs stimulate acid secretion, the effect they exert on pepsinogen secretion is unknown. The aim of this study was to investigate whether LTs stimulate pepsinogen secretion by isolated chief cells and to identify the intracellular messengers that mediate this action.
  
  
  METHODS
  Isolated chief cells were incubated with concentrations of LTB4, LTC4, LTD4, or LTE4 ranging from 0.1 pmol/L to 10 mumol/L, and pepsinogen release, intracellular calcium and inositol(1,4,5)-trisphosphate (IP3) concentrations were measured. Nitric oxide generation was determined by the amount of citrulline generated during incubation.
  
  
  RESULTS
  All four LTs caused a concentration-dependent stimulation of pepsinogen secretion with 50% effective concentration of 0.05-0.1 nmol/L and a dose-dependent increase in cytoplasmic free calcium and IP3 concentration. The LTB4 and LTD4 antagonists caused selective, concentration-dependent inhibition of LTB4- and LTD4-induced pepsinogen secretion, calcium mobilization, and IP3 generation. All four LTs increased NO generation, and the effect was inhibited by LTB4 and LTD4 antagonists and an NO synthase inhibitor NG-monomethyl-L-arginine and reversed by L-arginine. NG-monomethyl-L-arginine caused a 50%-60% reduction of LT-induced pepsinogen release. Each of the four LTs caused a fivefold increase in 5'-cyclic guanosine monophosphate.
  
  
  CONCLUSIONS
  LTs are powerful stimulators of pepsinogen secretion in isolated chief cells and act via occupancy of specific cell-surface receptors.
authors.affiliation: Dipartimento di Medicina Clinica, Patologia e Farmacologia, Università degli Studi di Perugia, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Fiorucci
authors.forename: E
authors.initials: E
authors.lastname: Distrutti
authors.forename: L
authors.initials: L
authors.lastname: Santucci
authors.forename: A
authors.initials: A
authors.lastname: Morelli
mesh_terms: D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D006152:Cyclic GMP / Q000096:biosynthesis; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism; D006168:Guinea Pigs; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015289:Leukotrienes / Q000494:pharmacology*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D010435:Pepsinogens / Q000378:metabolism*; D019323:omega-N-Methylarginine
chemical_list: D015289:Leukotrienes; D010435:Pepsinogens; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D015544:Inositol 1,4,5-Trisphosphate; D001120:Arginine; D007770:L-Lactate Dehydrogenase; D006152:Cyclic GMP; D002118:Calcium