Sertoli cells and ovarian granulosa cells (the FSH target)

Target gland or tissue · FSH Aromatase Inhibin B

FSH drives granulosa proliferation and aromatase, and in the testis supports spermatogenesis through Sertoli cells and androgen-binding protein. Both cells secrete inhibin B, the selective brake on FSH.

Traced from the start

  1. Gonadotrophin-releasing hormone pulse generator (arcuate nucleus)
  2. Gonadotroph — luteinising hormone and follicle-stimulating hormone
  3. Sertoli cells and ovarian granulosa cells (the FSH target)

Detail

Aromatase
Converts theca androstenedione and testosterone to oestrone and oestradiol; it is also active in adipose tissue, which is why obesity raises oestrogen in men
Inhibin B
Suppresses FSH only, which is why FSH rises before LH in the perimenopause as inhibin falls first
Anti-Mullerian hormone
A granulosa product used as an index of ovarian reserve; fetal Sertoli AMH causes Mullerian duct regression in the male
Barrier
Sertoli tight junctions form the blood-testis barrier

When it goes wrong

Seminiferous tubule damage from chemotherapy, mumps orchitis or Klinefelter syndrome

High FSH with low inhibin B and oligospermia, while LH and testosterone may still be near normal

Primary ovarian insufficiency before the age of 40

Amenorrhoea with FSH repeatedly above 25-40 IU/L and low oestradiol; hormone replacement is needed to protect bone and cardiovascular health

Practise this structure

2 questions in the bank tagged Feedback Axis.