endocrine fertility

Question 1

axis in males

Answer 1

GnRH= FSH/LH= testes produces testosterone (inhibin - feedback to hypothalamus and pituitary)

Question 2

axis in follicular phase for females

Answer 2

GnRH= LH/FSH= ovary produces oestradiol+ progesterone (inhibin - feedback)

Question 3

axis in ovulation for females

Answer 3

ovary produces more oestradiol, which causes more GnRH, leading to an LH surge= ovulation

Question 4

luteal phase

Answer 4

endometrium shed if implantation occurs

Question 5

define infertility, how common and cause

Answer 5

not able to get pregnant after 1 yr on regular unprotected sex

happens to 1 in 6 couples, caused by abnormalities in males or females

Question 6

what occurs in primary gonadal failure

Answer 6

low testosterone/ovary= high GnRH and LH/FSH

Question 7

what occurs in hypo/pituitary disease

Answer 7

low FSH/LH and low GnRH (GnRH can’t be measured), so low testosterone/oestradiol

Question 8

clinical features of male hypgonadism

Answer 8

low libido, impotence (no erection), small testes, less muscle and osteoporosis

Question 9

causes of male hypogonadism

Answer 9

hypo/pituitary disease- either pituitary disease or kallmans syndrome (low GnRH, often combined with lack of smell aka anosmia) or illness/underweight (due to low leptin- less reproductive hormones secreted

primary gonadal disease- either inherited (klinefelters) or acquired (testicular torsion+ chemotherapy)

hyperprolactinaemia (not common in men)

rarely androgen receptor deficiency

Question 10

investigating male hypogonadism

Answer 10

measure LH, FSH and testosterone- if low, MRI of pituitary needed

measure prolactin

measure sperm count- azospermia means NO sperm during ejaculation, oligospermia means less

analyse chromosomes for klinefelters

Question 11

treatment of male hypogonadism

Answer 11

replacement testosterone for all- if they want fertility, not possible for primary gonadal disease, but possible for hypo/pit disease with LH+ FSH mimicking injections (Hcg given)- testosterone alone won’t produce sperm

dopamine agonist for hyperprolactinaemia

Question 12

where testosterone produced

Answer 12

leydig cells, adrenal cortex, ovaries, placenta and tumours

Question 13

actions of testosterone

Answer 13

develops male genital tract

supports fertility as adult

secondary sexual features

anabolic effects (including bone)

Question 14

testosterone conversions

Answer 14

testosterone converted into dihydrotestosterone (DHT- active form) via 5alpha-reductase, or oestradiol via aromatase, which act on androgen and oestrogen receptor respectively (nuclear receptors)

Question 15

define amenorrhoea and types

Answer 15

absence of periods

primary- never had period before (often congenital)

secondary- someone whos had period before hasn’t had one for 3 months (ie cycle was working perfectly at one point, so rarely congenital)

oligomenorrhae- irregular periods

Question 16

causes of amenorrhoea

Answer 16

pregnancy/breastfeedin (hgih prolactin)

ovarian failure- can be premature ovarian failure (menopause by 40 rather than normal 51), ovariectomy/chemotherapy (toxic to ovaries) or turners (X chromosome missing)

gonadotrophin failure- hypo/pit disease, kallmanns syndrome, low BMI (due to low leptin) and the pill (switches off axis, so stop taking it every 4 years)

hyperprolactinaema

gonadal tumour= excess androgens

Question 17

investigating amenorrhea

Answer 17

pregancy test- MOST IMPORTANT

LH, FSH+ oestradiol- cycles are variable so won’t be very useful, but if all low, could indicate hypo/pituitary disease

day 21 progesterone- should have a rise if person has ovulated

prolactin/thyroid tests (high or low TSH can cause problems)

androgens (if high, can switch off axis)

chromosome analysis for turners

ultrasound scan of ovaries

Question 18

treatment of amenorrhoea

Answer 18

treat cause eg if low weight, make them eat

primary ovarian failure- become infertile, so give HRT: important as in premature failure, females have not received full dose of oestrogen= osteoporosis, so HRT vital

hypo/pit disease- HRT to replace oestrogen, and LH/FSH if fertility desired via IVF (like men)

Question 19

polycystic ovarian syndrome- incidence and effects

Answer 19

occurs in 1/12 women, and can lead to increased CVD and diabetes

Question 20

diagnosing PCOS

Answer 20

need 2 of the following- lots of cysts in ovaries on ultrasound, oligo/anovulation (lack of ovulation), and excess androgens

Question 21

features of PCOS

Answer 21

hirsutism (excess hair), problems with periods, and increased BMI

Question 22

treatment of PCOS

Answer 22

metformin- for insulin resistance

clomiphene- binds to oestrogen receptor, preventing -feedback, so axis vamped up

FSH/LH via IVF for fertility

Question 23

control of prolactin

Answer 23

TRH stimulates prolactin a bit, but main control is the inhibitory dopamine

Question 24

actions of prolactin

Answer 24

causes lactation, and reduces LH actions and GnRH pulsatility (released at regular intervals)

Question 25

causes of hyperprolacinaemia

Answer 25

dopamine-antagonists like anti-psychotics prolactinoma pituitary adenoma compressing stalk- prevents dopamine reaching pituitary PCOS hypothyroidism (high TRH) oestrogen/pregnancy/ lactation

Question 26

features of hyperprolactinaema

Answer 26

galactorrhoea- lactation lower GnRH/LH= hypogonadism prolactinoma- causes head ache/visual problems

Question 27

treatment of hyperprolactinaema

Answer 27

treat cause eg drugs dopamine agonists eg cabergoline (can help with prolactinoma) pituitar surgery