All of the following hormones have receptors on the cell surface, EXCEPT:: (A) Adrenalin, (B) Growth Hormone, (C) Insulin, (D) Thyroxine
Answer is D. 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