Changes in the Serum Levels of Estradiol and Changes in Expression of Estrogen Receptor Alpha in the Bone Tissue of Ovariectomized Wistar Rats

Estradiol is an estrogen steroid hormone and is produced basically within the follicles of the ovaries. The decrease in serum estrogens concentration at menopause disrupts the metabolic balance, changes the lipid profile leading to visceral obesity, which caused an increase in serum estradiol levels, through aromatase activity. Estrogen deficiency also is a reason for the development of osteoporosis.We investigated the serum estradiol levels and changes in bone alpha estrogen receptor expression in ovariectomized rats. For this purpose, we used 20 female Wistar rats at reproductive age - 2 months divided into 2 groups: group 1 (G1)-10 animals were ovariectomized and group 2 (G2)-10 of which were sham-operated. All animals of G1 showed weight gain compared to group G2. The results showed that the values of serum 17β-estradiol in rats of G1 statistically increased compared to G2 (p <0.05). Immunohistochemical analysis revealed no difference in estrogen receptor expression between the both groups. Histomorphological analysis of femur from G1 showed the presence of pronounced osteoporosis. Ovariectomy led to the development of obesity, which caused an increase in serum estradiol levels, through aromatase activity, but this process did not prevent bone tissue from developing osteoporosis.