pcos - help - drp450

[ArchivalUser]

Alright. What gives! Uworld says that in PCOS Clomiphene is used because the estrogen has a negative feedback on the hypothalamus and inhibits GnRH. Clomiphene would then suppress this negative feedback response resulting in increased LH and FSH. But then Goljan Rapid Review says that the estrogen has a positive feedback which is why there is increased LH.

So is it that Estrogen has a negative feedback on the Hypothalamus at the same time while having a positive feedback on the pituitaary? Or am I trying to make sense of contradictory information?

[ArchivalUser]

eostrogen has a negative feedback on both pituitary and hypothalamus ... however very high estrogen level has positive feedback instead which results in LH surge during ovulation ...

clomiphene is a estrogen analogue which does not exhibit estrogen activity, rather blocks estrogen activity resulting in dec. LH secretion ...bringing the LH : FSH back to normal ....

[ArchivalUser]

Thanks. So clomiphene causes a decrease in LH? How does that happen. Is it blocking the negative feedback at the receptor in the hypothalamus? And if so, how does that decrease LH? Would there not be an increase in GnRH then an increase in LH & FSH due to loss of negative feedback?

[ArchivalUser]

clomiphene basically blocks the positive feedback of estrogen on LH (remember estrogen at high dose causes positive feedback on LH causing LH surge which results ovulation and at low dose inhibit pituitary-hypophyseal system).

When u r using clomiphene u r blocking some of the estrogens in patinet's blood (remember that PCOS patients also have high estrogen level which results from the aromatization of the testosterone as the testosterone level is high due to high LH activity and also u know that PCOS pts are fat ... so lot of aromatizations)

So when the estrogen activity comes down .... it follows the normal menstrual cycle hormonal control ...

[ArchivalUser]

Thank you