title: Glutamine stimulates prostaglandin-sensitive Na(+)-H+ exchange in experimental porcine cryptosporidiosis.
abstract: OBJECTIVE
  Recent studies of piglet cryptosporidiosis showed an injury-induced impairment of sodium-glucose cotransport and a prostaglandin-mediated inhibition of neutral NaCl absorption. Because glutamine has been shown to stimulate both neutral and electrogenic Na+ absorption, this study examined the mechanism of prostaglandin-mediated inhibition of NaCl absorption and the effect of glutamine on these processes.
  
  
  METHODS
  Ileal mucosa from control and infected pigs was mounted in Ussing chambers for flux studies or incubated with [14C]glutamine or [14C]-glucose for metabolism studies.
  
  
  RESULTS
  Glucose and glutamine induced equivalent increases, 2-2.5 microEq.cm-2.h-1, in Na+ absorption and short-circuit current in control ileum. Despite a reduction in villous surface area to one third of the control, glutamine enhanced both neutral and electrogenic Na+ absorption in the infected ileum by 3.5 +/- 0.5 microEq.cm-2.h-1, whereas glucose was only half as effective (P < 0.05). In addition, glutamine was oxidized to CO2 at rates three times those of glucose. Indomethacin enhanced, whereas amiloride, prostaglandin E2, and Cl-free solutions inhibited the glutamine-induced neutral Na+ transport.
  
  
  CONCLUSIONS
  Glutamine-stimulated neutral Na+ absorption is mediated by a prostaglandin-sensitive apical Na(+)-H+ exchange mechanism. The heightened Na(+)-H+ exchange and tissue oxidation of glutamine suggest that glutamine is superior to glucose for use in oral rehydration solutions.
authors.affiliation: Center for Gastrointestinal Biology, North Carolina State University, Raleigh.
authors.forename: R A
authors.initials: RA
authors.lastname: Argenzio
authors.forename: J M
authors.initials: JM
authors.lastname: Rhoads
authors.forename: M
authors.initials: M
authors.lastname: Armstrong
authors.forename: G
authors.initials: G
authors.lastname: Gomez
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism; D003457:Cryptosporidiosis / Q000378:metabolism* / Q000473:pathology; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005973:Glutamine / Q000378:metabolism / Q000494:pharmacology*; D007082:Ileum / Q000473:pathology; D007213:Indomethacin / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000473:pathology; D010084:Oxidation-Reduction; D011453:Prostaglandins / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013552:Swine
chemical_list: D002712:Chlorides; D011453:Prostaglandins; D017923:Sodium-Hydrogen Exchangers; D005973:Glutamine; D012964:Sodium; D005947:Glucose; D007213:Indomethacin