Sertoli cells produce androgen-binding protein (ABP) in response to FSH. ABP maintains high intratesticular testosterone. What other critical function do Sertoli cells perform that is directly regulated by testosterone?

• A Sertoli cells produce testosterone directly via 17β-HSD under FSH control, bypassing Leydig cells
• B Sertoli cells secrete inhibin A (not inhibin B) to selectively inhibit FSH at the pituitary
• C Sertoli cells directly regulate Leydig cell LH receptor density via paracrine inhibin B
• D Sertoli cells form the blood-testis barrier (BTB) via tight junctions (claudin-3/11), sequestering post-meiotic spermatids from the immune system; testosterone (via AR) is required to maintain BTB integrity and support spermiogenesis ✓

Explanation

Sertoli cells are the 'nurse cells' of spermatogenesis with multiple essential functions. They form the blood-testis barrier (BTB) via tight junctions between adjacent Sertoli cells at the base of the seminiferous epithelium, created by claudin-3, claudin-11, and occludin. This creates immunological privilege for haploid spermatids (which express novel surface antigens that would otherwise be recognized as foreign). Testosterone, acting on androgen receptors in Sertoli cells, is essential for maintaining BTB integrity, supporting spermiogenesis (stages V–VIII in rodents), and for spermiation. FSH drives Sertoli cell proliferation (before puberty) and promotes inhibin B secretion (not inhibin A) for FSH feedback.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

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Written and medically reviewed by the StethoPrep medical team.