The action of anabolic steroids on bone in experimental animals.

Anabolic steroids are currently used in the treatment of established osteoporosis. It has been demonstrated that, at least partly, anabolic steroids increase bone density by stimulating bone formation. Very little is known about how anabolic steroids affect bone in experimental animals. Because bone studies in animals have been performed only with the anabolic steroid nandrolone, or its long-acting ester nandrolone decanoate (ND), we present a general overview in this paper of the effect of these anabolic agents in various steroid-affected animal models for osteoporosis, viz. gonadectomized rats, heparin-treated mice and intact or ovariectomized dogs. In rats and mice these agents increase longitudinal and periosteal bone growth and bone mass, thus demonstrating their anabolic action. They also decrease trabecular bone resorption in ovariectomized and orchidectomized rats, which indicates that they have anti-catabolic effects. In ovariectomized rats, ND was found to increase the mechanical strength of cortical bone, which is an important property in a drug that is intended to be used in treating established osteoporosis. In elderly dogs, ND was found to stimulate endosteal bone formation. These findings indicate that nandrolone and ND have beneficial effects on bone in both oestrogen and androgen-deficient animals.