Q8: Serum Gastrin levels are
increased by prolonged use of:
a) H2 Receptor blockers
b) Proton Pump Inhibitors
c) Antacids
d) Anticholinergics
Correct Answer: b
Explanation:
The most appropriate answer is
Proton Pump Inhibitors (PPI) because they irreversibly inhibit H+ /K+
-ATPase in stomach parietal cells. H2 blockers on the other hand
cause a reversible block of histamine H2 receptors resulting in decreased
production of H+. Since the PPI are irreversible blockers of the
Proton pump they cause a more sustained decrease in H+ production.
This, through positive feedback increases the secretion of Gastrin. Generally
increased acid (H+ ions) causes decreased production of Gastrin
& decreased acid (such as through PPI use) cause increase in Gastrin secretion.
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