MSH Produced by the pars inter media of pituitary causes in lower vertebrates :

Options

A. Darkening of skin
B. Light colouration of skin
C. Both
D. None of these

Answer

To answer the question regarding the function of MSH (Melanocyte Stimulating Hormone) produced by the pars intermedia of the pituitary gland in lower vertebrates, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Source of MSH**:
- MSH is produced by the pars intermedia of the pituitary gland. The pituitary gland has two main parts: the adenohypophysis (anterior pituitary) and the neurohypophysis (posterior pituitary). The pars intermedia is a part of the adenohypophysis.

2. **Understand the Function of MSH**:
- MSH stands for Melanocyte Stimulating Hormone. Its primary function is to stimulate melanocytes, which are cells responsible for producing melanin, the pigment that gives color to skin, hair, and eyes.

3. **Determine the Effect of MSH on Skin Color**:
- The action of MSH on melanocytes leads to an increase in melanin production. This results in skin darkening. Therefore, MSH is responsible for the regulation of skin pigmentation.

4. **Evaluate the Options Given**:
- The question provides multiple choices: skin darkening, skin light color, both, and none of these. Based on the function of MSH, we can conclude that it is responsible for skin darkening.

5. **Select the Correct Answer**:
- The correct answer is that MSH causes skin darkening in lower vertebrates.

### Final Answer:
**MSH produced by the pars intermedia of the pituitary causes skin darkening in lower vertebrates.**

---