Angiotensinogen is a protein produced and secreted by

Options

A. Macula densa cellls
B. Endothelial cells (cells lining the blood vessels)
C. Liver cells
D. Juxtaglomerular (JG) cells

Answer

To answer the question "Angiotensinogen is a protein produced and secreted by," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Angiotensinogen**:
- Angiotensinogen is a precursor protein that plays a crucial role in the regulation of blood pressure and fluid balance in the body.

2. **Identifying the Source**:
- Angiotensinogen is produced and secreted by specific cells in the body. The options provided are macula densa cells, endothelial cells, liver cells, and juxtaglomerular cells.

3. **Analyzing Each Option**:
- **Macula Densa Cells**: These cells are part of the nephron and are involved in sensing sodium concentration but do not produce angiotensinogen.
- **Endothelial Cells**: These cells line blood vessels and are not known for producing angiotensinogen.
- **Liver Cells**: The liver is known to produce various proteins, including angiotensinogen, which is secreted into the bloodstream.
- **Juxtaglomerular Cells**: These cells are responsible for releasing renin but do not produce angiotensinogen.

4. **Conclusion**:
- Based on the analysis, the correct answer is that angiotensinogen is produced and secreted by **liver cells**.

### Final Answer:
Angiotensinogen is a protein produced and secreted by **liver cells**.

---