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Potassium Excretion

RENAL PHYSIOLOGY

Low K’ Diet    Normal and High K* Diet

Physiologic Factors That Stimulate K* Secretion	Physiologic Factors That Stimulate K* Reabsorption	Factors That Alter K* Secretion (Stimulate)	Factors That Alter K^ł Secretion (Inhibit)
Aldosteronc Hyperkalemia	Low K* diet	Increased urine llow ratę Acute and chronic alkalosis Chronić acidosis	Acute acidosis _

J. Perkins

MS, MF.A «!BVI

Figurę 6.15 Potassium Excretion_

The kidneys are the primary route for excretion of K ’ trom Ilu* body, and the amount excreted vari«*s wilh dietary K' intake. On a low K* diet, only about 1% of the filtered load is excreted. With a normal or high K’ diet, varying amounts of K' are excrcted. Most of the K^- that is excreted under these conditions reflects K* that is secreted into the tubular fluid by the collecting duet. The principal celi of the col-lecting duet secretes K*, while the intercalated celi of the collectinę duet is thought to be involved in K' rcabsorption during a low k' diet. The mechanisms of K reabsorption by the proximal tubule thick ascending limb of Henle's loop are depicted in Figurę G.8. a' these are not influenced by dietary K*.

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