20. Male hormonal control of reproduction and infertility

Question 1

where is GnRH produced?

Answer 1

median eminence

Question 2

where is the median eminence

Answer 2

between hypothalamus + pit gland

Question 3

GnRh is released in a pulsatile manner - what does this mean?

Answer 3

periods when there is and when there is not Gn RH release

Question 4

what occurs between the pulses of GnRh secretion?

Answer 4

GnRH is replenished

Question 5

can GnRH secretion and replenishment occur at the samr time?

Answer 5

no

Question 6

what effects would a GnRH agonist cause?

Answer 6

overstimulation of GnRH secretion - no production

Question 7

what effects would a GnRH antagonist cause?

Answer 7

production of GnRH - but no secretion

Question 8

what does GnRH cause the release of

Answer 8

FSH and LH

Question 9

function of FSH

Answer 9

production of ABP

Question 10

function of ABP

Answer 10

binds and transports testosterone

Question 11

which cells does FSH act on

Answer 11

sertoli

Question 12

what is FSH negatively regulated by?

Answer 12

inhibin and follistatin

Question 13

what is FSH positively regulated by?

Answer 13

activin

Question 14

function of LH

Answer 14

causes leydig cells to produce testosterone

Question 15

what is LH negatively regulated by?

Answer 15

testosterone

Question 16

3 functions of testosterone

Answer 16

1. stimulate germ cells - sex differentiaiton
2. bone, skin, hair and accessory sex organs - post puberty
3. converted into dihydrotesotosterone (DHT)

Question 17

function of DHT

Answer 17

epiphysial closure of long bones

Question 18

3 diseases associated with this gonadotropins in males

Answer 18

1. Kallman’s syndrome
2. Kleinfelter syndrome
3. Complete testicular feminisation

Question 19

which disease involves a gene defect?

Answer 19

kallman’s syndrome

Question 20

which disease is X-linked recessive?

Answer 20

complete tesicular feminisation

Question 21

what is Kleinfelter’s syndrome caused by?

Answer 21

XXY - non-disjunction during meiosis

Question 22

describe the genetic background of Kallman’s syndrome

Answer 22

genetic mutation of kal-1 gene - which is on X ch - failure to regulate outgrown axons in nasal olfactory epithelium. GnRH cannt be produced

Question 23

wheere do GnRH neurones migrate to and form in foetal life

Answer 23

nasal epithelium to hypothalamus

Question 24

describe cause of complete testicular feminisation

Answer 24

inactivation of androgen receptor - causing androgen resistance

Question 25

what is complete testicular feminsation

Answer 25

genetically = male

physically and psychosocially = female

Question 26

which 2 disease result in hypogonadism>

Answer 26

kallman’s and kleinfelters syndrome

Question 27

3 sxs of kallmans syndrome

Answer 27

1. azoospermia
2. anosmia
3. lack of secondary sexual characteristics

Question 28

6 sxs of kleinfelters syndrome

Answer 28

1. azoospermia
2. underdevelopment of testes
3. learning difficulties
4. adipose build up
5. androen deficiency
6. gynaecomastia (enlargement of male breasts)

Question 29

3 sxs of complete testicular feminisation

Answer 29

1. primary amenorrhoae
2. lack of pubic hair
3. small inguinal testes

Question 30

treatment of kallman and klienfelters syndrome

Answer 30

tesosterone substituion

Question 31

3 treatment options for complete testicular feminsation

Answer 31

1. orchidectomy - surgical removal of testes
2. oestrogen sub after puberty
3. counselling