This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Hypergastrinemia is seen in all, EXCEPT: 
Select and explain. 
A. Atrophic gastritis, B. Zollinger Ellison syndrome, C. Prolonged acid suppressive medications, D. Fasting
D: Fasting
Answer: D: Fasting 
Explanation: G cells - specialised endocrine cells secrete gastrin. Food especially protein, peptides and amino acids stimulate gastrin secretion. Fasting and increased gastric acidity inhibit gastrin release. High gastric pH is a strong stimulus for gastrin release. MUST KNOW: Hypergastrinemia is seen in: 1. Atrophic gastritis 2. Prolonged use of acid suppressive medications 3. Zollinger Ellison syndrome Ref: Sleisenger and Fordtrans, Edition-9, Page-7.