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: Biochemistry
Calcium as a second messenger in hormone action involves all except 
Select and explain. 
A. Gastrin, B. Oxytocin, C. ADH, D. Insulin
D: Insulin
Answer: D: Insulin 
Explanation: The receptors for several protein hormones like insulin are themselves protein kinases which are switched on by binding of hormone.The kinase activity associated with such receptors results in phosphorylation of tyrosine residues on other proteins.Insulin is an example of a hormone whose receptor is a tyrosine kinase.Ref: DM Vasudevan, 7th edition, page no: 656, 318, 323