Which of the following statements is not correct regarding ACTH?

Options

A. It is secreted by the anterior lobe of pituitary.
B. It regulates skin pigmentation in human beings.
C. It acts on the adrenal cortex and it mainly stimulates the secretion of mineralocorticoids.
D. Its hypersecretion causes bronze-like pigmentation of skin.

Answer

To determine which statement regarding ACTH (Adrenocorticotropic Hormone) is not correct, we will analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Statement 1: "It is secreted by the anterior lobe of the pituitary."**
- ACTH is indeed secreted by the anterior lobe of the pituitary gland. This statement is correct.

2. **Statement 2: "It regulates skin pigmentation in human beings."**
- This statement is incorrect. Skin pigmentation in humans is primarily regulated by the hormone melanin, not ACTH. While ACTH can influence skin pigmentation indirectly through its effects on melanocytes, it is not the primary regulator. Therefore, this statement is not correct.

3. **Statement 3: "It acts on the adrenal cortex and it mainly stimulates the secretion of mineralocorticoids."**
- ACTH does act on the adrenal cortex, but it primarily stimulates the secretion of glucocorticoids (like cortisol) rather than mineralocorticoids (like aldosterone). However, it can have some influence on mineralocorticoid secretion as well. This statement is partially correct but can be misleading.

4. **Statement 4: "Its hypersecretion causes bronze-like pigmentation of the skin."**
- This statement is correct. Hypersecretion of ACTH can lead to increased melanin production, resulting in a bronze-like pigmentation of the skin, particularly in conditions like Cushing's disease.

### Conclusion:
The statement that is not correct regarding ACTH is **Statement 2: "It regulates skin pigmentation in human beings."**