Effect of thyroxine on B.M.R is

Options

A. Increase
B. Decrease
C. Uncertain
D. No effect.

Answer

**Step-by-Step Solution:**

1. **Understand the Terms:**
- BMR stands for Basal Metabolic Rate, which is the rate at which the body expends energy at rest to maintain vital functions.
- Thyroxine (T4) is a hormone produced by the thyroid gland that plays a crucial role in regulating metabolism.

2. **Role of Thyroxine:**
- Thyroxine is essential for the proper functioning of every cell in the body. It influences how quickly the body uses energy, makes proteins, and controls how sensitive the body is to other hormones.

3. **Effect of Thyroxine on BMR:**
- An increase in thyroxine levels leads to an increase in the basal metabolic rate. This is because thyroxine stimulates metabolic processes, leading to higher energy expenditure.

4. **Consequences of High Thyroxine Levels:**
- Excessive production of thyroxine can lead to conditions such as Graves' disease, which is characterized by an overactive thyroid and significantly elevated BMR.

5. **Conclusion:**
- Therefore, the effect of thyroxine on BMR is an increase. The correct answer to the question is "increased."

**Final Answer:**
The effect of thyroxine on BMR is an increase.

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