A dinner for Smith Math Students and Faculty will follow the lecture at Teapot Restaurant at 6pm.
PLEASE RSVP by March 23, 2005 if you would like to attend the dinner, by email or calling Julia Ellingboe at extension 3803.
Tea at 4 pm in the Math Forum on the 3rd floor Burton will precede the lecture.
ABSTRACT: “How does estradiol initiate the LH surge? A modeling approach.”
In vertebrates, ovulation is triggered by a surge of luteinizing hormone (LH) from the anterior pituitary. The precise mechanism by which rising estradiol from the ovaries initiates the LH surge in the primate menstrual cycle remains a mystery. The mystery is due in part to the bimodal nature of estradiol modulation of LH secretion, and in part to a controversy over the site of feedback action of estradiol. Over the menstrual cycle, the pituitary releases LH pulses of dramatically different amplitude in response to pulses of gonadotropin releasing hormone (GnRH) from the hypothalamus. During a normal cycle, the driving GnRH pulse frequency varies considerably, arguing for a site of estradiol action in the hypothalamus. However, in GnRH replacement therapies used for the treatment of certain infertility disorders, no variation in GnRH pulse frequency is required for an LH surge. Thus estradiol must also exert a feedback action within the pituitary, independently of the hypothalamus.
We use differential equations to explore possible underlying neuroendocrine mechanisms for the action of estradiol in the pituitary. Basing mathematical models as closely as possible on the experimental literature, two alternative (not necessarily exclusive) hypotheses have emerged from our numerical experiments. We will introduce the biology, discuss the models, and describe the ongoing bench experiments that the models have suggested.
The mathematics department gratefully acknowledges support for the Dickinson Lecture activities provided by the Borie Fund, established in memory of Ellen Borie, class of 1966.