Postmenopausal Women Estrogen and Progesterone Infusion
Status:
Completed
Trial end date:
2015-08-22
Target enrollment:
Participant gender:
Summary
The purpose of the study is to study the effects of aging, estrogen and progesterone on the
brain. Specifically, we want to look at how the hypothalamus and pituitary (two small glands
in the brain) respond to estrogen. The pituitary gland is controlled by the hypothalamus. The
hypothalamus secretes GnRH (Gonadotropin-Releasing Hormone) that signals the pituitary to
secrete the reproductive hormones, LH (Luteinizing Hormone) and FSH (Follicle Stimulating
Hormone). These hormones act on the ovaries and signal the ovaries to produce estrogen and
progesterone. Estrogen in the bloodstream then acts on the brain to modulate this system with
changes in LH and FSH. Early changes associated with low levels of estrogen are inhibitory
(estrogen negative feedback) while higher levels of estrogen (such as those present when a
follicle in the ovary is ready to ovulate) stimulate LH to cause ovulation (positive
feedback). This study will determine: 1) hypothalamic and pituitary levels of glucose uptake
(as a measure of brain metabolic activity) at baseline and in association with estrogen
negative feedback on LH (24 hr) and estrogen positive feedback on LH (72 hr); and 2) the
effect of aging on estrogen feedback on LH, assessing negative feedback (nadir ~ 24 hr) and
positive feedback (peak between 72 and 96 hr).