Androgen binding protein which helps in concentrating testosterone in the seminiferous tublue and which inhibits ICSH secreted by anterior pituitary and GnRH production by hypothalmus is secreted by

Options

A. Cells of Leydig
B. Sustentacular cells
C. Interstitial cells
D. Spermatogonia cells

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the source of androgen binding protein (ABP), which has two functions: concentrating testosterone in the seminiferous tubules and inhibiting the secretion of interstitial cell stimulating hormone (ICSH) and gonadotropin-releasing hormone (GnRH).

2. **Identifying the Relevant Structures**: In the testes, the seminiferous tubules are where spermatogenesis occurs. Within these tubules, there are two main types of cells: spermatogonia (which develop into sperm) and Sertoli cells (which support and nourish the developing sperm).

3. **Function of Sertoli Cells**: Sertoli cells play a crucial role in spermatogenesis. They provide nourishment to the sperm cells and are responsible for secreting androgen binding protein (ABP). ABP binds to testosterone, allowing it to be concentrated in the seminiferous tubules, where it is needed for sperm development.

4. **Role of Leydig Cells**: Outside the seminiferous tubules are Leydig cells (also known as interstitial cells), which produce testosterone. However, they do not secrete ABP.

5. **Inhibition of Hormones**: The ABP secreted by Sertoli cells also has an inhibitory effect on the secretion of ICSH from the anterior pituitary and GnRH from the hypothalamus, contributing to the regulation of male reproductive hormones.

6. **Conclusion**: Based on the functions described, the correct answer to the question is that androgen binding protein is secreted by Sertoli cells (also referred to as subtentacular cells).

**Final Answer**: Androgen binding protein is secreted by Sertoli cells (subtentacular cells).

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