Testosterone

Abstract

Testosterone has complex regulatory effects on bone acting directly as testosterone or after metabolism to dihydrotestosterone or estradiol. After puberty testosterone regulates skeletal growth and terminates longitudinal growth via estradiol binding to the estrogen receptor. The role and mechanism of action of testosterone in maintaining bone mass in men is not as clearly defined as the role of estradiol in women but current data supports the concept that it is the combined effect of testosterone and locally synthesized as well as circulating estradiol acting on their target receptors. There have been a number of trials of testosterone therapy in older men (summarized in Table 1). Low level..