Characterization of Prostaglandin G/H Synthase 1 and 2 in rat, dog, monkey, and human gastrointestinal tracts

Gastroenterology. 1996 Aug;111(2):445-54. doi: 10.1053/gast.1996.v111.pm8690211.


Background & aims: In the gastrointestinal tract, prostaglandins are implicated as important mediators of normal physiological processes. Prostaglandin G/H synthase (PGHS) is the first enzyme leading to the formation of prostaglandins. Two forms exist: the constitutive PGHS-1 and the inducible PGHS-2 isoforms. The purpose of this study was to examine the expression of PGHS-1 and -2 in gastrointestinal tissues.

Methods: PGHS-1 and -2 expression and activity were examined in rat, dog, monkey, and human gastrointestinal tracts by immunoblot and biochemical assays.

Results: PGHS-1 but not PGHS-2 protein was identified in all gastrointestinal tissues. PGHS-1 protein varied throughout the gastrointestinal tracts; interspecies differences were also noted. Immunohistochemical studies showed PGHS-1 staining of rat endothelial cells in all gastrointestinal regions; PGHS-2-specific staining was noted in a subset of macrophages in 3 of 22 rats examined. Elevated activity was shown in tissues expressing greater concentrations of PGHS-1 protein. Indomethacin, a nonsteroidal anti-inflammatory drug that inhibits both isoforms, inhibited prostaglandin synthesis, whereas NS-398, a selective PGHS-2 inhibitor, showed little or no inhibition of prostaglandin synthesis in gastrointestinal tissues.

Conclusions: These results indicate that prostaglandins produced in normal gastrointestinal tissue and required for normal physiological functioning are derived from the PGHS-1 isoform.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology
  • Cyclooxygenase Inhibitors / pharmacology
  • Digestive System / drug effects
  • Digestive System / enzymology*
  • Dogs
  • Endothelium / enzymology
  • Humans
  • Immunoblotting
  • Immunohistochemistry
  • Indomethacin / pharmacology
  • Isoenzymes / metabolism
  • Macaca mulatta
  • Macrophages / enzymology
  • Microsomes / drug effects
  • Microsomes / enzymology
  • Molecular Sequence Data
  • Nitrobenzenes / pharmacology
  • Prostaglandin-Endoperoxide Synthases / metabolism*
  • Rats
  • Saimiri
  • Sulfonamides / pharmacology


  • Anti-Inflammatory Agents, Non-Steroidal
  • Cyclooxygenase Inhibitors
  • Isoenzymes
  • Nitrobenzenes
  • Sulfonamides
  • N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide
  • Prostaglandin-Endoperoxide Synthases
  • Indomethacin