PCT does not reabsorb one of the following actively

Options

A. Glucose, amino acid, vitamin C
B. `75%of K^(+) and 70% Na^(+)`
C. Large amount of `Ca ^(2+)`
D. Creatinine, hippuric acid

Answer

To solve the question regarding which substance is not actively reabsorbed by the Proximal Convoluted Tubule (PCT), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Function of the PCT**: The Proximal Convoluted Tubule is responsible for the reabsorption of various substances from the filtrate back into the blood. It actively reabsorbs glucose, amino acids, vitamins, and certain ions.

2. **Evaluate the Options**:
- **Option 1**: Glucose, amino acids, and vitamin C.
- The PCT actively reabsorbs 100% of glucose and amino acids, as well as a significant amount of vitamin C. Therefore, this option is incorrect.

- **Option 2**: 75% Potassium and 70% Sodium.
- The PCT reabsorbs approximately 65% of sodium and potassium actively. Thus, this option is also incorrect.

- **Option 3**: Large amounts of calcium.
- While calcium is reabsorbed in the kidneys, the majority of calcium reabsorption occurs in the loop of Henle and distal convoluted tubule rather than the PCT. However, some calcium is still reabsorbed in the PCT, making this option incorrect as well.

- **Option 4**: Creatinine and hypuric acid.
- Creatinine is not actively reabsorbed by the PCT; it is primarily secreted. Hypuric acid is also not actively reabsorbed. Therefore, this option is correct.

3. **Conclusion**: Based on the evaluation of the options, the substance that the PCT does not actively reabsorb is **creatinine and hypuric acid**.

### Final Answer:
The correct answer is **Option 4: Creatinine and hypuric acid**.