Tamoxifen prevents bone loss in ovariectomized mice.

Bone density and mineral content of the femora were significantly decreased in ovariectomized mice compared with intact control animals. Tamoxifen treated ovariectomized mice did not develop any decrease either in the bone density or in calcium and phosphate content of the femora which were observed in ovariectomized mice. In addition, the weight of uterus in tamoxifen treated ovariectomized mice was the same as in intact controls. It was concluded that tamoxifen administered in vivo prevented the loss of bone mineral and uterus weight in ovariectomized mice and thus it showed a true estrogen like action in this respect.