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: Pharmacology
All of the following hormones have receptors on the cell surface, EXCEPT: 
Select and explain. 
A. Adrenalin, B. Growth Hormone, C. Insulin, D. Thyroxine
D: Thyroxine
Answer: D: Thyroxine 
Explanation: Hormones act on their specific receptors located on or within their target cells. Receptor activation by hormones is translated into response in a variety of ways. Thyroxine hormone has its receptor within the nucleus. This hormone penetrates the nucleus -> combines with its receptor --> alter DNA-RNA mediated protein synthesis. Ref: Essentials of Medical Pharmacology, 5th Edition, Page 214