Choose the correct statement.

Options

A. During the time of stress, cortisol acts as an anabolic hormone in muscle and adipose tissue
B. The posterior pituitary is connected to hypothalamus by a portal system
C. Prolonged lack of iodine has a significant effect on thyroxine secretion
D. Injection of calcitonin causes hypercalcemia

Answer

To solve the question "Choose the correct statement," we need to evaluate each of the provided statements one by one based on the information given in the video transcript.

### Step-by-Step Solution:

1. **Evaluate Statement 1:**
- Statement: "During the time of stress, cortisol acts as an anabolic hormone in the muscle and adipose tissue."
- Explanation: The video states that cortisol is a catabolic hormone, which means it breaks down stored energy (like glycogen) to provide glucose for energy during stress. Therefore, this statement is **false**.

2. **Evaluate Statement 2:**
- Statement: "The posterior pituitary is connected to the hypothalamus with the help of the portal system."
- Explanation: The video clarifies that the posterior pituitary is connected to the hypothalamus via nerve endings, not the portal system. Hence, this statement is also **false**.

3. **Evaluate Statement 3:**
- Statement: "Prolonged lack of iodine has a significant effect on thyroxine secretion."
- Explanation: The video explains that iodine is essential for the production of thyroxine. A prolonged lack of iodine leads to decreased thyroxine secretion, resulting in hypothyroidism and goiter. This statement is **true**.

4. **Evaluate Statement 4:**
- Statement: "The injection of calcitonin causes hypercalcemia."
- Explanation: The video indicates that calcitonin helps lower blood calcium levels by depositing calcium into bones and preventing its excretion. Therefore, an injection of calcitonin would lead to hypocalcemia, not hypercalcemia. This statement is **false**.

### Conclusion:
The correct statement among the options provided is the third one: "Prolonged lack of iodine has a significant effect on thyroxine secretion."

---