Question

Which of the following pituitary hormone is an opioid peptide?

• A. Alpha- melanocyte stimulating hormone
• B. Adrenocorticotrophic hormone
• C. Beta- endorphin
• D. Growth hormone

Hint:

Endogenous Opioid Peptides: $\beta$-Endorphin (from POMC), Enkephalins (from Proenkephalin), Dynorphins (from Prodynorphin).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Pro-opiomelanocortin (POMC) is a multifunctional prohormone precursor cleaved post-translationally into melanotropins, adrenocorticotropin, and endogenous opioid peptides.
Key Formula or Approach:
\[ \text{POMC} \longrightarrow \text{ACTH} + \beta\text{-LPH} \longrightarrow \alpha\text{-MSH} + \text{CLIP} + \gamma\text{-LPH} + \beta\text{-Endorphin (Endogenous Opioid)} \]

Step 2: Detailed Explanation:
In pituitary endocrinology and neurobiology:
- Beta-Endorphin ($\beta$-Endorphin) is a 31-amino-acid endogenous opioid peptide synthesized and secreted by the anterior pituitary gland and hypothalamus.
- It binds with high affinity to $\mu$-opioid receptors in the central and peripheral nervous system, mediating analgesia, stress euphoria, and pain suppression.

Step 3: Final Answer:
Thus, Beta-endorphin is an opioid peptide, matching option (C).