Testosterone and the Male Skeleton: A Dual Mode of Action

Table 1

Clinical parameters of men with aromatase deficiency or estrogen resistance.

	Aromatase deficiency	Estrogen resistance
Age of diagnosis	Newborn, 24–38 yrs	28.5 yrs
Bone phenotype	(i) Persistent linear growth	(i) Continuing linear growth into adulthood
	(ii) Unfused epiphyseal cartilages	(ii) Unfused epiphyses
	(iii) Delayed bone age	(iii) Delayed bone age
	(iv) Osteopenia/osteoporosis	(iv) Osteoporosis
	(v) Eunuchoid proportion of the skeleton	(v) Progressive genu valgum
	(vi) Progressively worsening of bilateral genu vagum	(vi) Eunuchoid proportions of the skeleton
Hormonal analysis	(i) Serum estradiol below the range of detection	(i) High concentration of serum estradiol, estrone, FSH, LH
	(ii) Gonadotropins and circulating testosterone ranging from normal to elevated	(ii) Normal serum testosterone
	(iii) Impaired glucose metabolism
	(iv) Insulin resistance
Effect of estrogen treatment	(i) Complete epiphyseal closure	No changes
	(ii) Spinal BMD increase
	(iii) Skeletal maturation