Proton Pump Inhibitors

Parietal cells H ion secretion depends on a H+,K+-ATPase pump-- promoting H K exchange

• H+,K+-ATPase located in apical membrane to and tubulovesicular apparatus of parietal cells
• Luminal surface of the membrane enzyme: exposed to gastric luminal acid

• Omeprazole and lansoprazole inhibit the proton pump, effectively irreversibly -- requiring synthesis of new enzyme protein
• Omeprazole and lansoprazole approved for treatment of:
  • duodenal ulcer
    •   may be used in conjunction with triple therapy
  • erosive esophagitis
  • gastric acid hypersecretory states, including Zollinger-Ellison syndrome