Which of the following is not metabolised in human body and therefore, used in determining glomerular filtration rate ?

Options

A. Insulin
B. Inulin
C. Cellulose xanthate
D. Toxic ketones

Answer

To solve the question of which substance is not metabolized in the human body and is used to determine the glomerular filtration rate (GFR), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding GFR**: The glomerular filtration rate is a test used to assess kidney function. It measures how well the kidneys filter blood.

2. **Identifying Substances Used in GFR Measurement**: Common substances used to measure GFR include creatinine, inulin, and urea.

3. **Metabolism of Substances**:
- **Inulin**: This is a polysaccharide that is not metabolized by the human body. It is freely filtered at the glomerulus and is not reabsorbed or secreted by the renal tubules, making it an ideal marker for measuring GFR.
- **Creatinine**: This is a waste product formed from muscle metabolism. While it is used to estimate GFR, it is produced in the body and can be slightly secreted by the renal tubules.
- **Urea**: This is a waste product formed from protein metabolism and is also produced in the body.

4. **Conclusion**: Among the options provided, inulin is the substance that is not metabolized in the human body and is used to determine GFR.

### Final Answer:
Inulin is not metabolized in the human body and is used in determining glomerular filtration rate (GFR).