Leydig cells and ovarian theca cells (the LH target)
Target gland or tissue · LH StAR Androgen synthesis
LH drives cholesterol through side-chain cleavage to androstenedione and testosterone in Leydig and theca cells. Theca androgen then crosses to the granulosa cell for aromatisation — the two-cell, two-gonadotrophin model.
Traced from the start
- Gonadotrophin-releasing hormone pulse generator (arcuate nucleus)
- Gonadotroph — luteinising hormone and follicle-stimulating hormone
- Leydig cells and ovarian theca cells (the LH target)
Detail
- In men
- Intratesticular testosterone reaches concentrations far above serum and is required for spermatogenesis
- In women
- Theca androgen is the obligatory substrate for oestradiol; excess theca activity produces the hyperandrogenism of polycystic ovary syndrome
- Ovulation
- The LH surge converts the follicle into the corpus luteum, the source of progesterone; hCG substitutes for LH as an ovulation trigger in assisted reproduction
When it goes wrong
Exogenous testosterone or anabolic steroid use
LH is suppressed and intratesticular testosterone collapses: testicular atrophy, azoospermia and infertility despite a normal or high serum testosterone
hCG-secreting germ cell tumour
LH-receptor stimulation causing precocious puberty in boys and gynaecomastia in men
Practise this structure
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