Effect of exogenous estrogen on male rats bone

Not only androgens however but also estrogens may be important for the growth and maintenance of the male skeleton. The estradiol treatment of intact male rats significantly decreased serum testosterone concentrations and the weight of seminal vesicles, however, not to the level of castrated animals. In spite of a low serum testosterone the administration of estradiol did not produce changes in the density, ash weight and mineral content of the tibia. In castrated rats with low serum testosterone bone density, ash weight and mineral content of the tibia were decreased, compared with intact controls. These our observation indicate that estrogen has a important role to retain bone mass in males as well as females.