This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
Characteristic feature of primary aldosteronism is - 
Select and explain. 
A. Low serum sodium, B. High plasma renin, C. Low serum potassium, D. High serum creatinine
C: Low serum potassium
Answer: C: Low serum potassium 
Explanation: hyper secretion of aldosterone increases renal distal tubular exchange of intra tubular sodium for secreted potassium and hydrogen ions, with progressive depletion of body potassium resulting in hypokalemia ( Harrison 17 pg 2260)