Estrogen and bone: insights from estrogen-resistant, aromatase-deficient, and normal men.

Findings from estrogen-resistant and aromatase-deficient men have provided important insights into the role of estrogen in the male skeleton during growth. Importantly, as reported elsewhere in this issue, these data also suggested dose-response relationships between estrogen and bone turnover. In addition, studies in these unusual patients have stimulated research on defining the role of estrogen in regulating bone metabolism in normal adult and aging men, providing further insights into estrogen regulation of bone metabolism not only in men, but also in women.