Positive feedback action of estrogen for inducing luteinizing hormone surge is associated with which of the following steroid hormone ratios in peripheral circulation?
Ovulation is the process by which the oocyte-cumulus is released from the follicle. Toward the end of the follicular phase, estradiol levels increase dramatically and exes a positive feedback effects at both the hypothalamus and anterior pituitary gland to generate the LH surge. So during ovulation peripheral blood shows elevated levels of estrogen. Progesterone is secreted by the corpus luteum, which is the remnant of the graffian follicle after the ova has been released. Thus, at the time of ovulation levels of progesterone is low, and its level rises only after ovulation. Ref: Williams Gynecology Chapter 15.
High estrogen : low progesterone
Low estrogen : high progesterone
Low estrogen : low progesterone
High estrogen : high progesterone