The ………..hormone is secreted by the ………..cells of kidneys stimulates the formation of erythrocyte.

Options

A. Erythropoietin , JG
B. Erythropoietin, Interstitial fibroblasts
C. Renin , JG
D. Renin. Macula densa

Answer

To solve the question, we need to identify the hormone responsible for stimulating the formation of erythrocytes (red blood cells) and the specific cells in the kidneys that secrete this hormone.

### Step-by-Step Solution:

1. **Understanding Erythropoiesis**:
- The process of red blood cell (RBC) production is known as erythropoiesis. It primarily occurs in the bone marrow.

**Hint**: Remember that erythropoiesis is the term used for the production of red blood cells.

2. **Identifying the Hormone**:
- The hormone that stimulates erythropoiesis is called erythropoietin. This hormone signals the bone marrow to increase the production of red blood cells when oxygen levels are low in the blood.

**Hint**: Think about the role of hormones in stimulating processes; erythropoietin is specifically linked to red blood cell production.

3. **Locating the Source of Erythropoietin**:
- Erythropoietin is secreted by specific cells in the kidneys. The correct cells that produce this hormone are the interstitial fibroblast cells.

**Hint**: Focus on the kidneys and their functions; interstitial fibroblast cells are crucial for erythropoietin production.

4. **Evaluating the Options**:
- The options provided in the question should be evaluated to find the correct match for the hormone and the cells:
- The correct answer is erythropoietin (the hormone) secreted by interstitial fibroblast cells (the cells in the kidneys).

**Hint**: Cross-check the options against your knowledge of kidney functions and hormone secretion.

5. **Final Answer**:
- The hormone is **erythropoietin**, and it is secreted by the **interstitial fibroblast cells** of the kidneys.

### Conclusion:
The complete answer to the question is: The **erythropoietin** hormone is secreted by the **interstitial fibroblast** cells of the kidneys, stimulating the formation of erythrocytes.