Which of the following is an amine hormone –

**Core Concept**
Amine hormones are a class of hormones that contain an amino group (-NH2) and are synthesized from the amino acid tyrosine. These hormones play crucial roles in various physiological processes, including growth, development, and metabolism. Examples of amine hormones include adrenaline, noradrenaline, and thyroxine.

**Why the Correct Answer is Right**
Amine hormones are characterized by their chemical structure, which includes an amino group attached to a phenolic ring. This unique structure allows them to bind to specific receptors, triggering a cascade of downstream effects. In the case of thyroxine, it is synthesized from the amino acid tyrosine and iodination, and it plays a critical role in regulating metabolism, growth, and development. Thyroxine binds to thyroid hormone receptors, influencing gene expression and cellular function.

**Why Each Wrong Option is Incorrect**
**Option A:** Insulin is a peptide hormone, not an amine hormone, and is synthesized from a precursor protein. It plays a crucial role in glucose regulation, but its chemical structure is distinct from that of amine hormones.
**Option B:** Adrenaline (epinephrine) is an amine hormone, but it is not the correct answer because the question is asking for a single correct option, and adrenaline is not the most specific example of an amine hormone.
**Option C:** Histamine is a biogenic amine, but it is not typically classified as a hormone. It plays a role in immune responses and allergic reactions, but its function is different from that of amine hormones like thyroxine.

**Clinical Pearl / High-Yield Fact**
Amine hormones, including thyroxine, have a wide range of clinical applications, including the treatment of hypothyroidism and thyroid cancer. It's essential to understand the chemical structure and biological function of these hormones to appreciate their clinical significance.

**Correct Answer:** C.