LH alone will cause ovulation

[MedGrl@2022]

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According to my examkrackers biology book. LH is MOST closely associated with ovulation as opposed to estrogen. It says that "LH alone will cause ovulation; estrogen alone will not." Does this mean that estrogen is not necessarily needed for ovulation?

 

[Hemorrage]

LH is released by the pituitary and most likely has other effects not including estrogen production. Remember estrogen is a class of hormones not a hormone itself- i think what the book is trying to say is that LH is more closely involved in ovulation vs estrogen members like estradiol

 

[Leonardo Noto]

The hormonal cascade that leads to follicle maturation and ovulation is complicated, but an LH spike is the signal that actually causes the follicle to rupture and ovulation to occur.

Dr. Leonardo Noto
www.leonardonoto.com or follow me on Twitter @DrLeonardoNoto

 

[stevvo111]

According to my examkrackers biology book. LH is MOST closely associated with ovulation as opposed to estrogen. It says that "LH alone will cause ovulation; estrogen alone will not." Does this mean that estrogen is not necessarily needed for ovulation?

yup, it's the LH surge that essentially causes ovulation (the bursting of follicle that releases the egg), estrogen and progesterone play key roles in building up the endometrium and preventing the ant pit from sending out more LH so more ovulation doesn't happen. Although low levels of it do indeed have a positive feedback to tell the ant pit to release more LH.

at high enough levels estrogen actually blocks ovulation- think birth control (it blocks LH and stuff...at high enough concentrations).

 

[osprey099]

the LH surge is what directly causes ovulation but you do need to have high estrogen level at that point as well. Although earlier on in the follicular phase, estrogen negatively feeds back on the hypothalamus and anterior pituitary to release less LH, once estrogen hits a certain level during the middle of the follicular phase, it starts to have a positive feedback cycle with the hypothalamus and Anterior pituitary so more and more LH gets released. Therefore, LH is what actually causes the primary oocyte to be ruptured from its attaching follicles but you need high levels of estrogen in order to have even higher levels of LH.

 

[jw1985]

the LH surge is what directly causes ovulation but you do need to have high estrogen level at that point as well. Although earlier on in the follicular phase, estrogen negatively feeds back on the hypothalamus and anterior pituitary to release less LH, once estrogen hits a certain level during the middle of the follicular phase, it starts to have a positive feedback cycle with the hypothalamus and Anterior pituitary so more and more LH gets released. Therefore, LH is what actually causes the primary oocyte to be ruptured from its attaching follicles but you need high levels of estrogen in order to have even higher levels of LH.

Thanks for this explanation! I could not understand what EK Biology was trying to say. It seemed very contradicting because their explanation was extremely brief and made no mention of a "threshold"