Name the endocrine cells of the testes.

Explanation

**Step-by-Step Solution:**

1. **Understanding Endocrine Cells**: Endocrine cells are specialized cells that secrete hormones directly into the bloodstream. They are ductless and play a crucial role in regulating various physiological processes.

2. **Location of Endocrine Cells in Testes**: In the testes, the primary endocrine cells are located in the interstitial spaces between the seminiferous tubules.

3. **Identifying the Specific Endocrine Cells**: The specific endocrine cells in the testes are known as Leydig cells. These cells are also referred to as interstitial cells.

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