This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Pharmacology
Aldosterone secretion is stimulated by which of the following? 
Select and explain. 
A. Hyperkalemia, B. Dopamine, C. Somatostatin, D. Atrial Natri uretic peptide (ANP)
A: Hyperkalemia
Answer: A: Hyperkalemia 
Explanation: Hyperkalemia stimulates aldosterone secretion and hypokalemia suppress aldosterone secretion. The serum potassium is an impoant independent regulator of plasma aldosterone levels (Independent of Renin and ACTH). Increased plasma K+ concentration causes direct stimulation of aldosterone by. Major Direct Stimulants for Aldosterone Secretion Angiotensin II (RAAS) (RAAS is the major regulator) Serum Potassium (Hyperkalemia stimulates and hypokalemia suppresses aldosterone secretion) ACTH (Acute) Factors Regulating Aldosterone secretion Factor Stimulatory Inhibitory Peptides Angiotensin ACTH Angiotensin III Vasopressin Endothelin Atrial natriuretic peptide Somatostatin Ions Plasma potassium Other Serotonin Dopamine Ref: Harrison 19th edition Pgno: 310