The parietal cell and its pump
Why PPIs beat H2 blockers, and why timing before breakfast matters.
Click any node for its role, or open a question below to light the causal path.
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Gastric parietal cells secrete acid through the H+/K+-ATPase (the proton pump), the final common step. Three stimulants converge on the cell: histamine at H2 receptors, acetylcholine, and gastrin. H2 blockers remove only the histamine input, so the other inputs keep some acid flowing and tolerance develops. PPIs inhibit the pump itself, irreversibly, every input is silenced until new pumps are synthesized (~24 h), which is why a short-plasma-half-life drug suppresses acid all day. Pumps are recruited by meals; PPIs taken 30-60 minutes before the first meal catch the largest population of active pumps.
Last reviewed 2026-08-15 · Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed.