Women and men have primarily three sex hormones: estrogen, progesterone and testosterone. Levels and ratios of these hormones differ between the sexes. Estrogen and progesterone are the dominant sex hormones in women whereas, testosterone is the predominant sex hormone in men. Understanding the interaction of estrogen, progesterone and testosterone is necessary to decipher symptoms and conditions caused by their imbalances."Estrogen" comes in three variations in the female body: Estrone (E1), Estradiol (E2), Estriol (E3). It is made in the ovaries, adrenal glands and fat cells. The scientific community often refers to all three forms collectively as "estrogen". However, each molecule has different actions and is present in different concentrations throughout a woman's life. Therefore, it is important to differentiate the three when referring to the "estrogen effects".
Estrone (E1) is the predominant form of estrogen in the postmenopausal period. It is manufactured in the fat cells primarily from androstenedione (a testosterone derivative). An increase in estrone correlates to increased body fat in the menopausal woman. Elevated estrone levels have been associated with increased incidence of breast tumors in animals.
Estradiol (E2) is the most active form of estrogen and is the predominant form of estrogen in women of reproductive age. Estradiol is made primarily by the ovaries and adrenals but is also made in small amounts by fat cells in the postmenopausal period.
Estriol (E3) is the weakest of the estrogens. It is primarily manufactured by the placenta during pregnancy. Estriol supplementation mainly affects the vaginal wall with little effect on the heart and bones. It also plays a role in hair, nail and skin health.
The scientific community often refers to all three forms (estrone, estradiol and estriol) collectively as "estrogen". However, each molecule has different actions. During the aging process, the ovaries cease to manufacture estradiol. The adrenal glands (small organs that sit onthe top surface of the kidneys) take over estrogen production in the form of estrone. The body transforms unused testosterone into primarily estrone and releases estrogen previously stored in fat cells.
Progesterone antagonizes the effects of estrogen, most importantly in the breast and uterus where it counteracts the stimulation of cell growth where overgrowth could lead to cancer. Progesterone is manufactured primarily by the corpus luteum on the ovary after monthly ovulation occurs and to a small degree by the adrenals. Progesterone is also manufactured by the placenta in great quantity during pregnancy. Progesterone is a precursor to most hormones making it extremely important far beyond the role it plays in the production of sex hormones.
For many reasons it is very important to maintain a healthy balance between these two sex hormones. Progesterone production diminishes significantly after menopause. Obese women who manufacture a significant amount of estrone in fat cells after menopause may not produce an adequate amount of progesterone, thereby increasing the likelihood of estrogen-related cancer, such as those of the uterus and breast.
More hormone discussion to follow...
Reference:
Schwartz ET, Holtorf K. Hormones in wellness and disease prevention: common practices, current state of the evidence, and questions of the future. Primary Care: Clinics in Office Practice 2008; 15(4)
Photomicrograph of estradiol crystals. Estradiol, the most potent of the natural estrogens, is used in its natural or semisynthetic form to treat menopausal symptoms.
