Chapter 41 - Androgen receptor expression and steroid action in bone

Abstract

Estrogen and androgen deficiency have been associated with the incidence of osteoporosis in postmenopausal women and elderly men over the last many decades. Estrogen and androgen function through signaling pathways that originate from binding to their cognate nuclear receptors, which collectively impact sexual function, growth and development, and skeletal health. These effects range from gain-of-function paradigms involving their cognate ligands that target these nuclear hormone receptor-mediated signaling pathways to loss-of-function paradigms that involve menopause/aging or rare allelic variants that abrogate ligand or receptor function. This review summarizes our current knowledge of the gain-of-function and loss-of-function attributes of these two steroid hormones with specific emphasis on androgens and male skeletal health.