Estrogen is produced in the ovaries, adrenal gland and testes. It’s regulated by Follicle Stimulating Hormone and stimulates the growth and development of the sexual organs. After puberty it stops the growth by closing the epiphyseal plate.
And of course it’s involved in the early phases of the menstrual cycle where growth of the endometrium/bloody supply takes place. If we look at the 28 day cycle, it peaks around day 14 and decreases. The release of progesterone also peaks around day 14. Both of them drop around day 28, giving way to the menses. If any of this is unfamiliar, review the physiology of the menstrual cycle.
Metabolic Effects of Estrogen
Sodium/Water Retention: Estrogen causes sodium and water retention. This is why women experience bloating more often than men.
Glucose Tolerance: Estrogen can alter glucose tolerance and can cause discovery of an underlying potential for diabetes.
Prevent Negative Calcium Balance: Estrogen prevents a negative calcium balance. The lack of estrogen causes decreased calcium and that has an impact on the bones. People with a lack of estrogen are more prone to osteoporosis. We used to have a therapy for osteoporosis using estrogen but a study came out a decade ago that led us to believe that estrogen is not as safe as we thought it could be. We knew already that it had a chance of causing uterine cancer and we knew we had to protect the uterus by giving a protective drug (progesterone) to be used with it. That wasn’t the problem. The study showed that estrogen increased the risk of heart attack, stroke and breast cancer. At that point, estrogen use was stopped for the purpose of osteoporosis and other alternatives were used.
However, in the case of post-menopausal women who are having severe hot flashes that makes it impossible for them to function, we give them estrogen and progesterone but we try to do it for a temporary time and keep the doses very low.
Carcinogenic Properties of Estrogen
Uterine Cancer: We know it causes uterine cancer if given alone, so it must be given together with progesterone. If a person has had a hysterectomy, however, they don’t have a uterus and so they can’t have uterine cancer.
DES (Diethylstilbestrol) was an estrogen utilized in the late 1950’s to 60’s to help prevent miscarriage. It did prevent miscarriage and had no effect on the mother. But they found out that if the child born was a female, by the teenage years, these kids were having cervical cancer. Luckily that was easily treatable but that drug was stopped.
Breast cancer: Birth control pills have conflicting data. Some studies show BC has a risk of breast cancer and others show a decreased risk.
Therapeutic Uses of Estrogen
We know it increases bone density but it’s no longer approved for this use.
Contraception: One therapeutic use is birth control that can be administered orally as a tablet or a patch on the skin. No matter how it’s utilized, progesterone is also with it.
Menopausal symptoms: Estrogen is utilized to treat post menopausal (hot flashes, vagina dryness; atrophic vaginitis)
Dysmenorrhea: When a woman has very painful periods, they are usually placed on birth control pills, possible for a short or long period of time. Usually they are put on it for three cycles to see if it goes away. Usually, but not always, being pregnant and giving birth to their first child tends to decrease dysmenorrhea.
Cancer: Estrogen’s are utilized for cancers stimulated by testosterone: prostate and testicular cancer. Testosterone is the opposite of estrogen. So at times, these people will be given estrogen to counteract the effect. This isn’t chemotherapy, it’s a palliative therapy.
Estrogen Side Effects
Nausea: Usually there is nausea in the first few days of a persons birth control medication but a tolerance develops and it goes away.
Mid cycle bleeding: In some individuals, the estrogen peaks too high in the middle of the cycle which causes too much of a thickening of the endometrial lining and bleeding occurs in the middle of the cycle. This is why you have birth control pills that have different formulations of estrogen and progesterone, to offset side effects that individuals are experiencing.
Breast tenderness: If they get too much breast tenderness, for example, they will be put on a birth control formulation that has less estrogen, just like for the mid-cycle bleeding.
Increased blood clotting: Estrogen is not recommended for anyone who is a smoker or anyone over 45 for this same reason.
Estrogen Drug List
- Mestranol and Ethinyl Estradiol (Estinyl): Both of these are two of the most common estrogen components in birth control pills (and always used with progesterone)
- Conjugated Estrogen (Premarin) orally is utilized for menopausal symptoms. The topical cream is used for vaginal symptoms.
- Estrodiol valerate (Delestrogen): Injection for menopausal symptoms.
- Estropipate (Ogen) also used for menopausal symptoms.
- Dienestrol (AVC) is a topical cream for menopausal vaginal symptoms as well.
Selective Estrogen Receptor Modulator (SERM)
This is a non-estrogen that stimulates the estrogen receptor in bone to prevent osteoporosis. This is a drug that can be used in the prevention of osteoporosis without the metabolic consequences of estrogen (carcinogenic, clotting, etc). The name of this drug is Raloxifene (Evista).
