AR and thymus atrophy: The central role of androgen-mediated thymic atrophy has been suggested on the basis of the presence of androgen receptors on the thymic epithelial cells (Savino and Dardenne, 2000) and developing thymocytes (Viselli et al., 1995) that are stimulated by circulating androgens, thus resulting in thymic atrophy (Olsen et al., 2001).