How do estrogen, ERT, and HRT work
Estrogens work by crossing the cell membrane into the cell and attaching to estrogen receptors on the nucleus of the cell. Each type of estrogen has a different ability to attach itself (receptor affinity) and to stay attached to the receptor on the nucleus (nuclear retention).
The stronger the receptor affinity, and the longer the nuclear retention time, the more potent the physiological action of the estrogen.
Estradiol not only has a strong receptor affinity but also increases the affinity of the receptor for estradiol. In contrast, estrone and estriol may decrease estradiol binding by lowering the cell’s affinity for estradiol. Estrone and estriol have only slightly lower receptor affinity than estradiol. Estradiol varies significantly in its nuclear retention time. While estradiol has a nuclear retention time of 6 to 24 hours, estriol is only 1 to 4 hours, with estrone higher than estriol, but still lower than estradiol. This means that once estradiol attaches itself to a cell, it sticks to it longer and has a stronger influence than estriol does.
The longer an estrogen occupies a receptor, the stronger its influence will be.
Thus, the estrogenic potency of a substance is determined by the duration of its occupation of receptors. Levels of a specific estrogen also can affect the duration of its influence on a cell. In fact, if estriol levels are in excess of normal non-pregnant levels for long periods of time, they can have the same effect on cells as estradiol does.
Research has demonstrated that continuously high estriol is as active as estradiol and less likely to exert any significant protective action. At normal physiological dosages, estradiol remains the most potent of the naturally occurring estrogens in the human body. However, conjugated estrogens (such as Premarin) and synthetic estrogens are more potent than estradiol.
Estrogen Replacement Therapy, ERT
Estrogens were first introduced as drugs in 1933, DES (diethylstilbestrol) being one of the first estrogen drugs. Subsequently, a combination estrogen-progestin birth control pill was developed, and by the mid-1960s the first wave of postmenopausal estrogen replacement use was gaining momentum.
In 1966, gynecologist Robert Wilson passionately declared that the pharmaceutical industry now offered Woman’s precious gift, the elimination of menopause, women’s physical, mental, and final emancipation. By the 1970s estrogen became one of the top five prescription drugs.
Women taking estrogen found that they had fewer hot flashes and no vaginal atrophy.
Their moods were better, their breasts firmer, and they had more energy.
However, studies soon showed that taking estrogen for longer than one year increased the risk of endometrial cancer. Estrogens’ popularity plummeted when the Food and Drug Administration issued a warning that the dose should be one-quarter of the amount used at that time, but admitted that this still might not be protective enough to negate the increased risk of cancer. The type of estrogen is another factor to consider.
The three types of active human estrogens
Estradiol, estrone, and estriol, can be prescribed alone or in combination. Estriol, although little-studied to date, maybe as effective as and safer than standard ERT; however, it is less potent and must be given in higher doses than the other two estrogens.
Some investigators have found that unopposed estriol (that is, without progesterone) does not cause endometrial hyperplasia (increase in the number of cells), However, it is believed that estriol, as with other forms of estrogen, should be given along with progesterone in postmenopausal women with or without a uterus.
The balancing effect of progesterone with estrogen likely affects other tissues besides the uterus. Because of the experience we have with estradiol and estrone, doctors often prescribe an estrogen formula developed by an expert in nutritional medicine. It consists of all three naturally occurring forms of estrogen: estradiol, estrone, and estriol. This “tri-estrogen” preparation includes these hormones in what he calculated to be the same proportion as they are found in premenopausal women and appears to minimize the risks of estrogen and maximize their benefits. It may be used along with natural progesterone and other hormones.
In getting the most out of our healthcare dollar, many of us have begun to voice concerns about the remedy most recommended by Western medicine for menopause and the years after hormone replacement therapy (HRT).
Many women view HRT, given most commonly in pill form, as drug treatment. They favour looking to alternative solutions, for the following reasons:
- They’re uncomfortable about taking medication for the rest of their lives.
- They’re worried about the possible link between HRT and cancer.
- They’re unwilling to continue with a medication that’s adding side effects and discomfort when it should be relieving their symptoms.
Even mainstream Western medicine, which has scoffed at alternative healing methods, has begun to reconsider its stance. Some physicians now work in affiliation with acupuncturists; some herbalists have clients who also take hormone therapy.
Perhaps most important, growing numbers of physicians recognize that a sound health plan requires participation and cooperation between patient and physician. These are the physicians who trust in their patients’ intelligence, good sense, and ability to make the right choices when given full information. This shift in attitude has much to do with pressure from consumers.
Hormone Replacement Therapy, HRT
Most doctors in the country now prescribe hormone replacement therapy (HRT), calcium supplementation, and vitamin D for osteoporosis. Occasionally the hormone calcitonin is prescribed. Etidronate, a substance that treats osteoporosis, showed promise for a few years but has not been approved by the Food and Drug Administration (FDA) for osteoporosis.
The new non-hormonal bisphosphonate drug Fosamax was approved for osteoporosis treatment by the FDA in late 1995.
It appears to halt spinal bone loss but it is not clear if it will be effective for the hip. Also, Fosamax works by interfering with the bone remodeling process and it is not clear if it leads to “worn-out” or unrepaired bone over the long haul.
There are reports of possible side effects that HRT brings like an increase in ovarian and breast cancer, weight gain, anxiety, fluid retention and etc. There is much research ongoing but we don’t yet know all the long-term effects of HRT, yet many doctors prescribe estrogen and progestogens for the duration of our life.
So is it possible to do this the “natural” way?