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: Physiology
Maximum contraction of gall bladder is seen with 
Select and explain. 
A. CCK, B. Secretin, C. Gastrin, D. Enterogastrone
A: CCK
Answer: A: CCK 
Explanation: Bile salts are the most important cholerectic or the substance that increases bile secretion. Cholecystokinin (CCK) is the most important cholagogue or substance that increases the contraction.