Growth hormone activity is

Options

A. Unaffected by thyroxine
B. Increased by thyroxine
C. Decreased in thyroxine
D. None of above

Answer

### Step-by-Step Solution:

1. **Understanding Growth Hormone (GH)**:
- Growth hormone, also known as somatotropin or human growth hormone (HGH), is a peptide hormone that plays a crucial role in growth, cell reproduction, and cell regeneration in humans and other animals.

2. **Source of Growth Hormone**:
- GH is secreted by the anterior lobe of the pituitary gland, which is located at the base of the brain.

3. **Role of Thyroxine**:
- Thyroxine is a hormone produced by the thyroid gland. It is known to influence various metabolic processes in the body, including growth.

4. **Interaction Between Thyroxine and Growth Hormone**:
- Research and biological understanding indicate that thyroxine has a stimulating effect on the activity of growth hormone. This means that when thyroxine levels are increased, the activity of growth hormone also increases.

5. **Evaluating the Options**:
- The options provided are:
- A) Unaffected by thyroxine
- B) Increased by thyroxine
- C) Decreased in thyroxine
- D) None of the above
- Based on the understanding that thyroxine increases the activity of growth hormone, the correct answer is **B) Increased by thyroxine**.

### Final Answer:
The activity of growth hormone is **increased by thyroxine** (Option B).

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