The ovaries synthesize E2, the most biologically active estrogen. E2 accounts for most of sex specific changes that begin during puberty like monthly ovulation & menstruation and the development of secondary sex characteristics.
The hypothalamus secretes gonadotropin-releasing hormone (GnRH) stimulating the pituitary gland to secrete follicle stimulating hormone (FSH) and luteinizing hormone (LH). Once puberty hits, the hypothalamus secrets GnRH in pulses creating peaks and valleys. FSH and LH stimulate ovarian follicles to develop and secret hormones. As the ovarian follicles develop, the follicular cells develop into theca cells and granulosa cells. Theca cells synthesize progesterone; granulosa cells synthesize estrogen. How much of each hormone is secreted is directly related to the phases of the menstrual cycle.
On average, menstrual cycles last 28 days. The cycle is centered around a surge of LH and FSH on day 14, which makes ovulation possible. Variations in FSH and LH levels result in variations of estrogen and progesterone levels. The follicular phase is the two weeks leading up to ovulation where mostly estrogen is produced. The luteal phase is the two weeks after ovulation where mostly progesterone is produced.
There are no more theta or granulose cells to secret any more hormones. E2 levels decrease and cause many symptoms leading up to menopause like hot flashes and night sweats. Some estrogen is still being synthesized by the adrenal glands and the fat cells in the body, but this estrogen is not E2, it's E1 (estrone).
Our free assessment quantifies your symptoms to see if hormone therapy is right for you. We're here to help you feel the way you want to feel.