Structure which has no role in endocrine secretion?

Options

A. Duodenal epithelium
B. Testes
C. Adrenal medulla
D. SubmaXillary gland

Answer

To determine which structure has no role in endocrine secretion, we will analyze each of the given options:

1. **Diodenal Epithelium**: The diodenal epithelium is part of the gastrointestinal tract and contains endocrine cells that secrete hormones such as gastrin, secretin, and cholecystokinin. Therefore, it does play a role in endocrine secretion.

2. **Testis**: The testis is a male reproductive organ that functions as an endocrine gland by producing hormones, particularly androgens like testosterone. Thus, it also has a role in endocrine secretion.

3. **Adrenal Medulla**: The adrenal medulla is the inner part of the adrenal glands and is responsible for producing hormones such as adrenaline and noradrenaline, which are crucial for the body's response to stress. This structure is involved in endocrine secretion as well.

4. **Submaxillary Gland**: The submaxillary gland is a type of salivary gland that primarily produces saliva, which contains enzymes and electrolytes for digestion. It does not produce hormones and is not classified as an endocrine gland. Therefore, it has no role in endocrine secretion.

Based on this analysis, the structure that has no role in endocrine secretion is the **Submaxillary Gland**.

### Final Answer:
**Submaxillary Gland**