Estrogen is one of the main sex hormones in the body. It is mainly produced by the ovaries, but can be produced in men and women by other tissues like fat (adipose) tissue, the brain and the reproductive organs. There are receptors for estrogen on almost every cell tissue in the body from the bone to the brain. There are three different types of estrogen: estrone (E1), estradiol (E2) and estriol (E3). Each form of estrogen will have a slightly different effect on the same tissue.
Menstrual Cycle
Once a female hits puberty, the menstrual cycle starts. Estrogen is responsible for causing development of the sex organs including breast tissue. Estrogen is one of the main signals that starts menstruation.
The menstrual cycle is a matter of hormone communication between two parts of the brain called the hypothalamus and the anterior pituitary and the ovaries. During the cycle, estradiol is released to thicken the lining of the uterine wall to prepare for implantation from an impregnated egg. The estradiol will raise to higher levels than normal and then drop off.
The estradiol sends the signal to the anterior pituitary to cause ovulation. If there is no pregnancy, the body will shed the thick lining of the uterine wall, thus starting the period.
Some birth control pills use a combination of progesterone and estradiol to prevent pregnancy. If the estradiol remains high, instead of dropping off, there will be no ovulation.
Pregnancy Signal
Once the body becomes pregnant, estriol is released from the fetus and the uterus. Estriol is the main form of estrogen during pregnancy and is also a sign of the health of the fetus. Estrogen will also play a function in the development of the breast tissue and preparation for milk.
Health Effects
The Association of Women for the Advancement of Research and Education (Project AWARE) states that having an estrogen deficiency can lead to a number of problems including changes in mood, loss of bone mass, vaginal dryness and increased likelihood of urinary tract infections. Additionally, a lack of estrogen has been linked to increased cholesterol which can lead to heart problems or risks for heart disease.
Functions in Men
While it has been known that estrogen is present in males, it was believed that estrogen normally had a negative effect in men. In 2005, a Polish health journal, Przeglad Lekarski, published an article that found that male bodies had estrogen receptors and estrogen production, and levels in the male blood are higher than post-menopausal women. Estradiol has been found to be responsible for initiating spermatogenesis in men. Estradiol has also been linked to bone strength, sexual maturation and cholesterol metabolism. The cholesterol metabolism regulation could help with heart health and the prevention of atherosclerosis.
References
- "Selected Topics from Basic Sciences to Clinical Competency:" Nikita Vizniak, BSc, DC; 2003.
- Project Aware: Estrogen Functions
- National Institutes of Health: Male Estrogen
