Endocrine Regulation of Male fertility

Question 1

What is testosterone produced by and what are its functions?

Answer 1

|It is produced by Leydig cells. Its functions depends on the age of the person. It is involved in:
- Growth,
- Skeletal muscles,
- Epiphyseal plates,
- Larynx growth,
- Secondary sex characteristics
- Erythropoiesis and behavior
- In adults it is involved in muscle mass, mood, bone mass, libido, body shape, erectile function and spermatogenesis

Question 2

What are the cells of the testes?

Answer 2

• Leydig cells which secrete testosterone to promote sperm development.
  Sertoli cells which make up the blood testes barrier, remove damaged spermatocytes and secrete androgen binding hormone

Question 3

What are the clinical features of hypogonadism in children and adults

Answer 3

Children - Slow growth in teens, no pubertal growth spurt, lack of secondary sexual development.
Adults - Low mood, poor libido, erectile dysfunction, hot flushes/sweats, poor muscle bulk, poor energy, sparse body/facial hair, gynaecomastia, gynoid weight gain, short phallus/reduced testicular volume and low trauma fractures

Question 4

What are the tests for suspected hypogonadism?

Answer 4

• Bloods: Early morning, fasting testosterone. Free testosterone (>200), total testosterone (>10) and SHBG.
• Do LH and FSH to determine if pituitary or testicular cause
• Others depend on testicular or pituitary pathology so can do: Semen analysis, pituitary screen/MRI, karyotyping, testicular ultrasound

Question 5

What are the blood results/name of disorder if hypogonadism is due to pituitary or testicular cause

Answer 5

Pituitary - Hypogonadotropic hypogonadism . So there will be low LH/FSH and low testosterone.
Testicular - Hypergonadotrophic hypogonadism. High LH/FSH but low testosterone

Question 6

What are some causes of hypogonadotrophic hypogonadism?

Answer 6

• Pituitary disease (prolactinoma),
• Head injury,
• Kallmann’s
• Functional hypothalamic hypogonadism (caused by excessive exercise, weight change, physical or psychological stress or systemic illness)

Question 7

What id Kallmann’s syndrome?

Answer 7

• Failure of GnRH cells to migrate to hypothalamus. It is associated with aplasia/hypoplasia of olfactory lobes, causing anosmia/hyposmia.
  May also be associated with deafness, renal agenesis and cleft lip/palate

Question 8

|What is the diagnosis and underlying genetics of Kallmann’s syndrome

Answer 8

• Anosmia in 75%. There will be low testosterone and low FSH/LH but the rest of the pituitary function is normal. May have absent olfactory bulb.
• Can be X-linked (KAL1), autosomal dominant (KAL2) or autosomal recessive (KAL3)

Question 9

What are some causes of primary gonadal disease?

Answer 9

• Chromosomal defects eg, Kleinfelters.
• Seminiferous tubule or Leydig cell failure. May occur following trauma, chemo.
• Cryptorchidism

Question 10

What is Klinefelter’s syndrome

Answer 10

• Extra X chromosome so the karyotype is 47 XXY (+/- mosaicism)
• It is a hypergonadotrophic hypogonadism as seminiferous tubules regress and Leydig cells do not function.

Question 11

What is the presentation and treatment of Klinefelter’s syndrome?

Answer 11

• Delayed puberty, reduced testicular volumes, reduced secondary male sexual characteristics, persistent gynaecomastia, azospermia, behavioral issues.
• Treat with androgen replacement (IM or topical), psychological support and fertility counselling (hCG, recombinant LH/FSH and GnRH pumps).

Question 12

What are the side effects of testosterone replacement therapy?

Answer 12

• Mood issues (aggression),
• Libido issues,
• Increased haematocrit/polycythaemia
• Lower UT symptoms,
• Acne,
• Gynaecomastia