endocrine fertility Flashcards
axis in males
GnRH= FSH/LH= testes produces testosterone (inhibin - feedback to hypothalamus and pituitary)
axis in follicular phase for females
GnRH= LH/FSH= ovary produces oestradiol+ progesterone (inhibin - feedback)
axis in ovulation for females
ovary produces more oestradiol, which causes more GnRH, leading to an LH surge= ovulation
luteal phase
endometrium shed if implantation occurs
define infertility, how common and cause
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
what occurs in primary gonadal failure
low testosterone/ovary= high GnRH and LH/FSH
what occurs in hypo/pituitary disease
low FSH/LH and low GnRH (GnRH can’t be measured), so low testosterone/oestradiol
clinical features of male hypgonadism
low libido, impotence (no erection), small testes, less muscle and osteoporosis
causes of male hypogonadism
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
investigating male hypogonadism
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
treatment of male hypogonadism
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
where testosterone produced
leydig cells, adrenal cortex, ovaries, placenta and tumours
actions of testosterone
develops male genital tract
supports fertility as adult
secondary sexual features
anabolic effects (including bone)
testosterone conversions
testosterone converted into dihydrotestosterone (DHT- active form) via 5alpha-reductase, or oestradiol via aromatase, which act on androgen and oestrogen receptor respectively (nuclear receptors)
define amenorrhoea and types
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
