reproductive hormones Flashcards
what are the two groups of reproductive hormones ?
estrogens and androgens
what is the most potent form of the estrogens ?
estradiol
what is the most potent form of testosterone ?
DHT
what are the steroid hormones carried by ?
SHBG
sex hormone binding globulin
where are the SHBG made?
in the liver
bind androgens more than estrogen
what is estrogen amplification ?
because SHBG binds more to androgens than estrogen , which increases the level of free estrogen which is the effective version
hence the amplification
this effect is amplified with high levels of SHBG
what are the clinical effects of low vs high SHBG ?
in men : gynecomastia
in women : hirsutism
what is the association between estrogen levels and cirrohsis ?
in cirrohsis there is decreased breakdown of estogen
along with decreased production of SHBG
hence an amplification of the estrogen effect resulting in gynecomastia , palmar erythema , spider nevi , impotence
clincal effect of high estrogens and low androgens
what are the levels of release associated with reproductibe hormone release ?
hypothalamus : GnRh
pituitary : FSH, LH
testes ovaries
release f ndrogens and estrogens
what are the levels of FSH and LH before puberty ?
low
what is the pattern in which GnRH is released in ?
pulsatile manner
how does GnRH allow for the release of LH and FSH from the pituitary gland ?
through the Gq protein system with IP3 second messenger
what is the GnRH agonist ?
leuroplide
resistant to degradation
what is the difference in effect between using lueroplide for a long time vs chronic use ?
short term use - increases the release of LH and FSH
long term use - decreases the release of Lh and FSH
what are the uses of leuroplide ?
1- administration in a pulsatile manner - to stimulate FSH and LH , may be used for infertility
2- in a continous manner - to suppress the levels of LH and FSH
what syndrome is associated with absence of GnRH ?
Kallman syndrome
imapired migration of GnRH neurones form origins in the olfactory bulb to hypothalamus
what are the key features associated with kallmans syndrome ?
hypogonadism
anosmia - cannot smell
Low GnRH , low FSH , LH , testosterone
small testes
delayed puberty
what messenger system is associated with FSh, LH, TSH and HCG ?
all associated with cAMP second messenger
what is the mechanism of amenorrhea in anorexia ?
decreased GnRH pulsation
because leptin is required for GnRH formation
leptin in anorexia is low
what is GnRh secretion inhibited by ?
estrogen , androgens and progesterone
through negative feedback 0
what is the effect of exogenous steroid consumption on GnRh levels ?
decreases GnRH
what are the levels of GnRH in association with menopause ?
increased GnRH due to lack of negative feedback
what are the levels of GnRH in association with androgen insensitivity syndromes ?
increase in GNRh , due to also lack of negative feedback
where is FSH and Lh produced ?
anterior pituitary
what is the target organ in association with LH and FSH ?
LH - ovarian theca interna cells
FSH - ovarian granulosa cells , testicular sertoli cells
