Estrogen and Its Effects Essay Example

pump was implanted into the femur near the ankle. 17 beta-estradiol, 17 alpha-estradiol, or phosphate-buffered saline was infused for eight days before the bones were examined. Initially, the removal of the ovaries caused a 50% loss in trabecular bone volume in the secondary spongy layer of the bone.

The local infusion of 17-beta-estradiol restored the trabecular bone volume to 75% and 85% of the control levels, decreased the relative bone breakdown levels, and increased osteoblast numbers, while the saline had no effect, as to be expected. Infusion of 17-alpha-estradiol had no effect on trabecular bone volume or resorption, but increased the osteoblast numbers to a slight extent. From these findings, it was concluded that estrogen, when delivered directly to the bone, both inhibits bone resorption and stimulates bone formation.

Research done by Bradford and Gerace at the University of Buffalo in New York found that estradiol helps to preserve bone density and maintain bone structure is by stopping the activation of an enzyme called caspase-3. Caspase-3 is the main enzyme in starting organized cell death of osteoblasts, and since studies suggest that estradiol decreases cell apoptosis in osteoblasts, inhibiting caspase-3 would be the first step in this process. To establish the effect of estradiol on caspase-3 activity, one group of human osteoblasts was treated with estradiol for 24 hours and another group was left untreated.

Both groups were then exposed for another 24 hours to etoposide, a drug used in chemotherapy that promotes apoptosis. The results of this test showed that caspase-3 activity decreased in cells treated with estrogen, but increased in cells not treated with estrogen. This supports the hypothesis that estradiol does have an effect on

apoptosis in bone cells, and that without it, cell death will increase and bone density will diminish. In addition to its effects on bone health, estrogen also has a huge effect on the cardiovascular system.

Studies have shown that it increases the levels of HDL, or “good” cholesterol, decreases the levels of LDL, or “bad” cholesterol, and relaxes and dilates blood vessels so that blood flow will increase. There is also evidence that estrogens contribute to the maintenance of the health of the endothelium, or the lining of the blood vessels, thus further protecting the cardiovascular system from plaque and heart disease. With menopause, estradiol levels drop, and so these effects on the heart and blood vessels are lowered, giving postmenopausal omen a higher risk of heart disease than premenopausal women. A study done by Kim and Levin in 2006 at the University of California states that 17-beta-estradiol typically has a protective property on the cardiovascular system, and that it decreases the amount of cell death in cardiomyocytes, or heart muscle cells. To test this theory, female rats had their ovaries surgically removed, allowed to recover, and then randomly chosen to be given pellets containing estradiol or placebo pellets.

One week after this took place, they underwent deliberate injury to the carotid artery. Two weeks after the injuries, the animals’ organs were examined. In the mice that had received the pellets containing estrogen, smooth muscle cells multiplied much faster and to a greater extent than the mice that only received placebo pellets. It also increased the healing rate of the endothelium of the carotid artery walls. This data suggests that estradiol does have a great effect on

cardiovascular health, protection, and repair.

A separate experiment done by Gouva and Tsatsoulis at the University of Ioannina Medical School in Greece suggests that estradiol could possibly prevent the development of atherosclerosis in postmenopausal women. This was tested by observing Macaca fascicularis monkeys who had their ovaries removed and then assigned to hormone replacement therapy – a daily dose of 17-beta-estradiol given orally. When the therapy was started after the removal of the ovaries and well after the start of atherosclerosis, there was no effect in the vessels.

However, when therapy was given to monkeys immediately after the surgery, in the early stages of atherosclerosis, there was a 50% reduction in plaque formation on the vessel walls. This suggests that estradiol does, in fact, have an effect on the endothelium, and, if given early enough, can help prevent the formation of plaque on the artery walls and thus help prevent atherosclerosis. In conclusion, estradiol has always been known to be incredibly important for the reproductive cycles of women, but recent developments have shown that it is essential for the health of other organs and systems in the body as well, including the liver and brain.