The steroid responsible for balance of water and electrolytes in our body is

Options

A. Insulin
B. Melatonin
C. Testosterone
D. Aldosterone

Answer

**Step-by-Step Solution:**

1. **Understanding Steroid Hormones:**
- Steroid hormones are derived from cholesterol. They are lipid-soluble and can easily pass through cell membranes to bind with specific receptors inside the target cells.

2. **Identifying the Options:**
- The options provided are insulin, melatonin, testosterone, and aldosterone. We need to identify which of these is a steroid hormone responsible for water and electrolyte balance.

3. **Analyzing Each Option:**
- **Insulin:** This is a peptide hormone, not a steroid hormone. It is composed of amino acids and is primarily involved in glucose metabolism.
- **Melatonin:** This hormone is derived from the amino acid tryptophan and is involved in regulating sleep patterns, not water or electrolyte balance. Hence, it is also not a steroid hormone.
- **Testosterone:** This is indeed a steroid hormone, but its primary role is in the development of male characteristics and reproductive functions, not specifically in water and electrolyte balance.
- **Aldosterone:** This is a steroid hormone classified as a mineralocorticoid. It is produced by the adrenal glands and plays a crucial role in regulating sodium and potassium levels in the body.

4. **Understanding the Role of Aldosterone:**
- Aldosterone promotes the reabsorption of sodium in the kidneys, which leads to water retention, thus helping to maintain blood volume and blood pressure. It also promotes the secretion of potassium.

5. **Conclusion:**
- Based on the analysis, the steroid responsible for the balance of water and electrolytes in our body is **aldosterone**.

**Final Answer: Aldosterone**

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