ADH influences

Options

A. Absorption of PCT
B. Absorption in DCT
C. Secretion in LOH
D. All of these

Answer

To answer the question regarding the influence of Antidiuretic Hormone (ADH), we will analyze each option provided and determine which one accurately reflects the role of ADH in the renal system.

### Step-by-Step Solution:

1. **Understanding ADH**: Antidiuretic Hormone (ADH), also known as vasopressin, is a hormone produced by the hypothalamus and released from the posterior pituitary gland. Its primary function is to regulate water balance in the body.

2. **Evaluating Option 1 - Absorption in Proximal Convoluted Tubule**:
- The proximal convoluted tubule (PCT) is indeed a site for reabsorption of various substances such as glucose, amino acids, and vitamins.
- However, ADH does not significantly influence the reabsorption processes in the PCT. Therefore, this option is incorrect.

3. **Evaluating Option 2 - Absorption in Distal Convoluted Tubule**:
- The distal convoluted tubule (DCT) is where the reabsorption of ions such as sodium, chloride, and calcium occurs.
- ADH plays a crucial role in increasing the permeability of the DCT and the collecting ducts to water, thus influencing water reabsorption. This makes this option correct.

4. **Evaluating Option 3 - Secretion in the Loop of Henle**:
- The loop of Henle is primarily involved in the concentration of urine and does not significantly involve ADH in its secretion processes.
- Therefore, this option is also incorrect.

5. **Evaluating Option 4 - All of These**:
- Since options 1 and 3 are incorrect, this option cannot be correct either.

### Conclusion:
The correct answer is **Option 2 - Absorption in Distal Convoluted Tubule**. ADH influences the reabsorption of water in the distal convoluted tubule and collecting ducts, thereby playing a significant role in water balance.