Which of the following vitamins has some physiological effects similar to those of parathormone ?

Options

A. Vitamin A
B. Vitamin D
C. Vitamin C
D. Vitamin B

Answer

To determine which vitamin has physiological effects similar to those of parathormone (parathyroid hormone), we can follow these steps:

### Step-by-Step Solution:

1. **Understand Parathormone Function**:
- Parathormone, secreted by the parathyroid glands, regulates serum calcium concentration. It affects the bones, kidneys, and intestines to maintain calcium levels in the blood.

2. **Identify the Role of Calcium in the Body**:
- Calcium is essential for various physiological functions, including muscle contraction, nerve transmission, and blood coagulation. The regulation of calcium levels is crucial for overall health.

3. **Look for Vitamins with Similar Effects**:
- We need to find a vitamin that also plays a role in calcium regulation and absorption, similar to parathormone.

4. **Consider Vitamin D**:
- Vitamin D, specifically its active form known as 1,25-dihydroxycholecalciferol, has been shown to have effects on calcium metabolism. It promotes the absorption of calcium and phosphate in the intestines, kidneys, and bones.

5. **Mechanism of Action of Vitamin D**:
- The active form of Vitamin D increases the formation of calcium-binding proteins in the intestines, enhancing calcium absorption. It also stimulates the formation of calcium-stimulated ATPase and alkaline phosphatase in epithelial cells, which further aids in calcium absorption.

6. **Conclusion**:
- Since Vitamin D has physiological effects that promote calcium absorption and regulation similar to those of parathormone, the answer to the question is Vitamin D.

### Final Answer:
**Vitamin D**