Estrogen and Its Effects Essay

1335 Words Mar 9th, 2012 6 Pages
Jenna Gunselman
Biochemistry Extra Credit Paper
Estrogen and Its Effects Estrogens are steroids that are important in the reproductive cycles of humans and some animals, and they are the main female sex hormones. They easily diffuse across cell membranes, and once they are inside, they bind to estrogen receptors to control many genes and their expressions. In human women, there are three types of estrogen: estradiol, which is the dominant form of estrogen in women who are not pregnant, estrone, which is produced during menopause, and estriol, which is found in pregnant women.
Estradiol is the most potent of the three types of estrogen found in women, almost ten times stronger than estrone and almost eighty times stronger
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Sprague-Dawley rats, which are typical laboratory albino rats, had their ovaries surgically removed, and 14 days after the surgery, a polyethylene tube connected to a 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.

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