In adipose tissue and bone by contrast, another distal promoter--promoter I. The importance of this unique aspect of the tissue-specific regulation of aromatase expression lies in the fact that the low circulating levels of estrogens which are observed in postmenopausal women have little bearing on the concentrations of estrogen in, for example, a breast tumor, which can reach levels at least one order of magnitude greater than those present in the circulation, due to local synthesis within the breast.
Thus, the estrogen which is responsible for breast cancer development, for the maintenance of bone mineralization and for the maintenance of cognitive function is not circulating estrogen but rather that which is produced locally at these specific sites within the breast, bone and brain. In breast adipose of breast cancer patients, aromatase activity and CYP19 expression are elevated.
The other types of oestrogen are called oestradiol and oestriol. Oestrone is primarily produced by the ovaries as well as by adipose tissue and the adrenal glands. It has a much weaker biological activity than oestradiol.
Oestrone is the major type of oestrogen hormone produced in any quantities in postmenopausal women. Very little is known about how the production of oestrone is controlled. Because oestrone is less active than oestradiol, it is thought that oestrone may act as a reservoir that can be converted into oestradiol as needed.
Increased oestrone production can occur in women with breast cancer and in men undergoing treatment for testicular or prostate cancer which reduces testosterone production.
Obese women also produce more oestrone from their fat tissues. In , researchers at American University in Washington, D. This research is hoped to help those with neurodegenerative disorders such as Parkinson's disease. Estrogen can also help with ovarian cysts. Antonella Lavelanet, an obstetrician at Boston Medical Center. Oral contraception pills and the patch or ring, which have similar mechanisms of action, can help suppress ovulation. There are many times throughout a person's life when estrogen levels may change.
For example, estrogen levels naturally increase during puberty and during pregnancy. Estrogen levels fall after menopause , or when a woman stops menstruating.
This reduction in estrogen production can cause symptoms such as hot flashes, vaginal dryness and loss of sex drive. Estrogen levels also decrease after childbirth. Other conditions that can cause estrogen levels to drop include hypogonadism or diminished function of the ovaries and polycystic ovarian syndrome. Extreme exercise and anorexia can also cause a decrease in estrogen levels because women with low body fat may not be able to produce adequate amounts of estrogen.
Some postmenopausal women with nonalcoholic fatty liver disease NAFLD have long durations of estrogen deficiency. Recent research has found that this deficiency could increase the risk of having more severe fibrosis, according to a study published in the journal Hepatology. Estrogen is found in most oral birth control pills along with the hormone progestin. Estrogen helps stop ovulation during pregnancy, and birth control pills mimic this effect by regulating the levels of estrogen and thereby preventing ovulation from occurring.
If you are having problems with menopause symptoms , such as hot flushes and mood swings, you may choose to go on hormone replacement therapy HRT. HRT includes oestrogen taken in the form of a tablet, gel or skin patch, and can be very effective in easing menopausal symptoms. Having too much oestrogen can lead to minor problems such as acne and constipation , or more serious conditions such as breast cancer.
Having too little oestrogen can cause problems such as poor bone growth and menopausal symptoms. Treatment is available for these conditions, so see your doctor if you have concerns. The causes of breast cancer are complex, involving many factors. However, it is known that oestrogen can help breast cancer cells grow.
Women who have been exposed to more oestrogen — for example, because they reached puberty early or went through menopause late — have an increased risk of breast cancer. Women who reach menopause at the normal age, but whose bodies have naturally high concentrations of oestrogen, also have an increased risk.
Oestrogen taken in the form of combined hormone-based medicines that contains both oestrogen and progestogen , including combined HRT and the pill, can lead to an increased risk of breast cancer too. Often, however, these risks are small, so talk to your doctor if you are concerned about breast cancer.
The risk is also reduced if you stop using these medicines. Learn more here about the development and quality assurance of healthdirect content. What exactly are fibroids and are they dangerous?
Read information on the diagnosis, management and treatment of fibroids. Read more on Jean Hailes for Women's Health website. The combined hormonal contraceptive pill the Pill is made up of two hormones, an oestrogen and a progestogen. These hormones are similar to the ones made in your ovaries.
There are many causes of osteopenia and osteoporosis. Learn about these different factors and how they may affect bone density. Most breast cancers need the hormone estrogen to grow and survive, and effective cancer treatments work by starving the cancer of estrogen. However, estrogen is important in maintaining bone strength and protecting bones.
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