[Changes in calcium, phosphate, magnesium and sodium content in bones of ovariectomized rats]

Bilateral ovariectomies (OVX) or sham surgeries-respectively-were performed in two lots of ten female Wistar rats, 90 days old. Food was available ad libitum to sham rats, and it was restricted to OVX ones. At 15, 30, 45 and 90 days, a segment of their tails was sectioned. At 180 days all rats were sacrificed and the left femurs were excised. With the tail's bones and the femurs we determined Ca++, PO4(-3), Mg++ y Na+ concentration. After 15 days, no significant differences inter lots were observed (p < 0.05) in all ions contents. After 30 days Ca++ value was significantly less (p < 0.05) in the OVX rats than in the sham ones. After 45 days all the analyzed OVX rats ions were significantly less (p < 0.05) than the sham values. That difference inter lots was greater after 90 days. Finally, day 180th gave a decrease in the OVX rat values-from the femur-as follows: for Ca++ 31%, for PO4(-3) 29%, for Mg++ 31.6% and for Na+ 29%. Our results shown that in 90 days old ovariectomized rats, the concentration of calcium, phosphate, magnesium and sodium in the tail bones is a good indicator of bone mass loss, after 45 days of ovariectomy.