Male Hypogonadism

Question 1

How is testosterone made?

Answer 1

Leydig cells

Question 2

What kind of hormone is testosterone?

Answer 2

Sterois

Question 3

How does Testosterone circulate in the blood?

Answer 3

Bound to SHBG or albumin

Question 4

What enzyme reaction activates testesterone?

Answer 4

Testosterone -> dihydrotestosterone by 5-alpha reductase.

Question 5

Where is testosterone activated?

Answer 5

In target tissues once it is free.

Question 6

What is the role of testosterone?

Answer 6

• Growth: sex organs, muscle, epiphyseal plates, larynx, secondary sex characteristics.
• Other: Erythropoiesis, behaviour
• Adults: Muscle mass, mood, bone mass, libido, body shape.
• Fertility: Libido, erection and spermatogenesis.

Question 7

What is the role of sertoli cells?

Answer 7

Maintain blood-testes barrier.
Remove damaged spermatocytes
Secrete androgen binding protein which locks testosterone in the tested.

Question 8

What are the child symptoms of hypogonadism?

Answer 8

• Slow growth in teens
• No pubertal growth spurt
• Lack of secondary sexual development
• Small testes and phallus

Question 9

What are the adult symptoms of hypogondadism?

Answer 9

- Small testes and short phallus
 low mood 
- poor libido
- erectile dysfunction 
- low muscle bulk/power 
- poor energy 
- sparse body/facial hair 
- gynacomastia 
- lots of hair on head.

Question 10

What size of testes would be seen on an orchidometer in early puberty?
Mid puberty?
Late puberty?
Adult?

Answer 10

Early: 4-6
Mid: 8-10
Late: 12-15
Adult: 20-25

Question 11

How do you test for hypogonadism?

Answer 11

• Early morning testosterone (should be surge in the morning)
• Free testosterone (normally >200)
• Total testosterone (normally >16)
• SHBG
• LH/FSH (is it pituitary cause?

Question 12

How would you test fertility in males?

Answer 12

• Semen analysis: 1-3 days after last ejaculation, should be 2-5ml volume.
• Check count, motility and morphology.

Question 13

In hypogonadotrophic hypogonadism where is the problem?

Answer 13

Hypothalamus or pituitary.

Question 14

In primary gonadal failure, where is the problem?

Answer 14

Testicles.

Question 15

Give examples of causes of hypogonadotrophic hypogonadism?

Answer 15

• pituitary surgery
• radiotherapy
• pituitary tumour
• prolactinoma (high prolactin supresses LH and FSH)
• ead injury
• Kallmans syndrome,

Question 16

What causes Kallmans syndrome?

Answer 16

Failure of cell migration of GnRH cells to the hypohlamus from the olfactory placode.

Question 17

How is Kallmans syndrome inerited?

Answer 17

Most commonly X-linked. Absence of KAL1 gene. 
Autosomal dominant (KAL2)
Autosomal recessive (KAL3)

Question 18

What are the symptoms of kallmans syndrome?

Answer 18

Same as hypogonadotropic hypogonadism with added symptom of anosmia or hyponosmia.

• small penis and testes, lack of 2ndry sex characteristics, poor libido, erectile dysfunction, low muscle bulk, gynacomastia etc.
• may have cryptorchidism, deafness, renal agenesis and cleft lip/palate.

Question 19

Describe testosterone, FSH, LH and prolactin in primary gonadal failure?

Answer 19

low testosterone

normal FSH, LH and prolactin.

Question 20

List causes of primary gonadal failure?

Answer 20

• Trauma
• Chemotherapy
• Radiotherapy
• Multisystem disorders
• Kleinfelters
• Myotonic dystrophy

Question 21

What is the gnetic abnormality in Kleinfelters?

Answer 21

XXY

Question 22

When does gonadal failure manifest in Kleinfelters?

Answer 22

At puberty

Question 23

How is primary gondalal failure managed?

Answer 23

• Androgen replacement: HypoG treatment: oral, IM or topical. BUT this wont concentrate enough in the testes to regain fertility.
• Physcological support and fertility councilling.

Question 24

List problems with androgen replacement therapy?

Answer 24

• Mood issues (aggression or behaviour change)
• Libido increased
• Increased haematocrit (increased risk of stroke and heart disease)
• Prostate enlargement (increased chance of BPH or cancer)
• Gynacomastia due to increased aromatase increasing oestrogen.