Androgens and osteoporosis

Androgen receptors are present in relevant numbers in osteoblasts. Stimulat ion of androgen receptors in osteoblastic bone marrow stromal cells inhibit s the differentiation of osteoclasts in the bone marrow cavity. Androgens n ot only inhibit osteoclastogenesis but also increase cortical bone formatio n mainly by stimulating periosteal bone formation. Clinically, androgen act ion is crucial for the gain of bone mass during puberty and the maintenance of bone mass after puberty. Therefore, androgen replacement is necessary i n hypogonadal men. However, the role of androgen replacement in partial and rogen deficiency still remains unclear. Thus far, only testosterone has est ablished its role in androgen replacement. However, further clinical and ba sic research should better define the selective role of androgen versus oes trogen receptor stimulation in male skeletal homeostasis.