gonads

Question 1

5 clinical features of male hypogonadism

Answer 1

loss of libido, impotence, small testes, decrease muscle bulk, osteoporosis

Question 2

4 causes of male hypogonadism

Answer 2

hypothalamic-pituitary disease (secondary gonadal disease), primary gonadal disease, hyperprolactinaemia, androgen receptor deficiency

Question 3

3 examples of hypothalamic-pituitary disease causing male hypogonadism

Answer 3

hypopituitarism, Kallmans syndrome (anosmia and low GnRH), illness/underweight (e.g. leptin or triggering hypothalamic amenorrhoea)

Question 4

features of Kallmans syndrome

Answer 4

congenital condition causing failure of GnRH secretion, majority also with failure of smell (anosmia as olfactory nerves migrate with GnRH neurones in foetal development); no secondary sexual characteristics

Question 5

2 classificatons of primary gonadal disease causing male hypogonadism

Answer 5

congenital and acquired

Question 6

congenital primary gonadal disease causing male hypogonadism

Answer 6

Klinefelters syndrome (XXY)

Question 7

2 acquired primary gonadal disease causing male hypogonadism

Answer 7

testicular torsion (ischaemia), chemotherapy

Question 8

4 investigations for male hypogonadism

Answer 8

LH, FSH and testosterone levels, prolactin, sperm count, chromosomal analysis (Klinefelters XXY)

Question 9

what is done if all 3 of LH, FSH and testosterone levels are low

Answer 9

indicates hypothalamic pituitary disease so MRI on pituitary

Question 10

define azoospermia

Answer 10

absence of sperm in ejaculate

Question 11

define oligospermia

Answer 11

reduced numbers of sperm in ejaculate

Question 12

major treatment for male hypogonadism

Answer 12

replacement testosterone if not wanting fertility; once every 3 months

Question 13

treatment for fertility if secondary gonadal disease (hypothalamus or pituitary disease) in male hypogonadism

Answer 13

subcutaneous gonadotrophins (LH and FSH) to produce sperm and testosterone; twice a week

Question 14

treatment for hyperprolacinaemia in male hypogonadism

Answer 14

dopamine agonist

Question 15

5 endogenous sites of production of androgens

Answer 15

interstitial Leydig cells of testes (male), adrenal cortex (male and female), ovaries (female), placenta (female), tumours (male and female)

Question 16

4 main actions of testosterone

Answer 16

development of male genital tract, maintains fertility in adulthood, control of secondary sexual characteristics, anabolic effects (muscle, bone)

Question 17

% of circulating testosterone is protein bound

Answer 17

98%

Question 18

2 outcomes of tissue-specific processing of free testosterone

Answer 18

5a-reductase to dihydrotestosterone (active form in men), aromatase to 17B-oestradiol (active form in female)

Question 19

what receptor does dihydrotestosterone act via

Answer 19

androgen nuclear receptor

Question 20

what receptor does 17B-oestradiol act via and location

Answer 20

oestrogen nuclear receptor e.g. brain and adipose tissue (in obese men, lots of adipose tissues cause testosterone to favour aromatase rather than 5a-reductase)

Question 21

4 clinical uses of testosterone

Answer 21

increase: lean body mass, muscle size and stength, bone formation and bone mass (in young men), libido and potency)

Question 22

treatment of infertility in males

Answer 22

testosterone won’t restore fertility, so requires treatment with gonadotrophins to restore normal spermatogenesis