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Insulin Na/K ATPase Potassium — FRCA Primary MCQ

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HardPhysiology - Endocrine & MetabolicInsulin Na/K ATPase PotassiumFRCA Primary

A beta2 agonist is used as an adjunct during treatment of severe hyperkalaemia. Which action is shared with insulin in producing a fall in plasma potassium?

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Correct answer: C — Stimulation of skeletal-muscle Na+/K+-ATPase activity

The best answer is “Stimulation of skeletal-muscle Na+/K+-ATPase activity”. Both insulin and beta2 agonists lower plasma potassium predominantly by increasing cellular uptake through Na+/K+-ATPase stimulation. This is redistribution, not elimination. They do not bind potassium, block potassium channels or reduce filtration. The potassium burden remains present and requires monitoring and, when indicated, definitive removal.

Reference: RCoA, Primary FRCA syllabus: https://www.rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf; Canonical and alternative pathways of GLUT4 recruitment: https://pmc.ncbi.nlm.nih.gov/articles/PMC13116035/