Which ONE of the following statements about rennin is CORRECT?

Options

A. It is secreted by adrenal glands.
B. It converts angiotensinogen to angiotensin.
C. It is secreted by peptic cells of gastric glands into the stomach.
D. It is a hormone.

Answer

### Step-by-Step Solution:

1. **Understanding Renin**:
- Renin is an enzyme that plays a crucial role in the regulation of blood pressure and fluid balance. It is primarily produced in the kidneys.

2. **Identifying the Source of Renin**:
- Renin is secreted by the juxtaglomerular cells of the kidneys, not by the adrenal glands or gastric glands. This helps eliminate options that incorrectly attribute its source.

3. **Function of Renin**:
- The primary function of renin is to convert angiotensinogen (a protein produced by the liver) into angiotensin I. This is an important step in the renin-angiotensin-aldosterone system (RAAS), which regulates blood pressure.

4. **Evaluating the Statements**:
- **Statement 1**: "It is secreted by the adrenal gland." - Incorrect, as renin is secreted by the kidneys.
- **Statement 2**: "It converts angiotensinogen to angiotensin." - This statement is partially correct, but it is important to note that renin converts angiotensinogen to angiotensin I, not just angiotensin.
- **Statement 3**: "It is secreted by peptic cells of gastric glands into the stomach." - This statement is incorrect since renin is not secreted by gastric glands but is produced in the kidneys.
- **Statement 4**: "It is a hormone." - Incorrect, as renin is an enzyme, not a hormone.

5. **Conclusion**:
- The correct statement about renin is that it is secreted by the juxtaglomerular cells of the kidneys and plays a role in converting angiotensinogen to angiotensin I.

### Correct Answer:
- The correct statement about renin is that it is an enzyme produced in the kidneys, and it converts angiotensinogen to angiotensin I.