K+

From Anvita Health Wiki

Contents 1 Introduction 2 More General Terms 3 Additional Terms 4 Internet Database 5 References

Introduction

• The total body K+ content in an adult is about 2500-3000 meq. About 98% of K+ is intracellular. Concentration of K+ is about 160 meq/L intracellularly & 3.5-5.0 meq/L extracellularly. K+ is the main intracellular cation & the K+ gradient across the cell membrane provides the force behind the negative potential & electrical excitability of cells. The Na+/K+ ATPase maintains the intracellular K+ concentration.

• Mechanisms regulating extracellular K+ concentration:

• renal

• most of the filtered K+ is resorbed by the proximal convoluted tubules & loop of Henle
• K+ in the urine is usually excreted by the collecting tubules under the influence of aldosterone
• factors increasing secretion of K+ in the urine

• increased urine flow rate
• increased distal tubule Na+ concentration
• increased mineralocorticoids

• aldosterone
• glucocorticoids have some mineralocorticoid activity

• increased urinary HCO3-

• urinary K+ may vary from 5-100 meq/L
• non-renal

• insulin: stimulates Na+/K+ ATPase because Na+ accompanies movement of glucose intracellularly
• beta-2 adrenergic receptor agonists

• increase activity of Na+/K+ ATPase

• aldosterone via effects on the GI tract
• acid-base balance

• acidosis favors movement of K+ out of cells
• alkalosis favors movement of K+ into cells

• Dietary K+ occurs as potassium phosphate. Generally, green leafy vegetables, fruits, & root vegetables are good dietary sources of K+ A dietary K+ intake of 120 mEq/ da or more is safe for healthy people, since excess K+ is excreted in the urine. However, patients with renal insufficiency, adrenal insufficiency, the elderly, & patients on ACE inhibitors, ARBs, NSAIDs, or potassium-sparing diuretics may need to monitor K+ intake (& serum K+). [1]

More General Terms

• monovalent cation
• metal ion

Additional Terms

• hypokalemic (K+ depleting) agent
• potassium (K+) in serum & urine
• potassium acetate
• potassium bicarbonate (Effer-K, K-lyte)
• potassium chloride (KCl)
• potassium citrate (Urocit K)
• potassium hydroxide (KOH)
• potassium iodide (KI, Thyro-Block, Irostat)
• potassium phosphate (KH2PO4)
• potassium [K, kalium]

Internet Database

PubChem: 813

References

1. Prescriber's Letter 15(9): 2008 Potassium Content of Foods and Salt Substitutes Detail-Document#: [1] (subscription needed) [2]

K+