[Hypogonadism and osteoporosis]

Hypogonadism, whether caused by primary gonadal failure or secondary gonadotropin deficiency, is associated with osteoporosis. Even gonadotropin-releasing hormone therapy for endometriosis causes a decrease in bone mineral density by reducing serum estradiol level. Recent interesting studies of a male patient with a nonsense mutation in the estrogen receptor gene, a girl with missense mutation in the aromatase gene, and knock-out mice targeting estrogen receptor gene suggest that estrogen is very important to maintain normal bone density even in a male. Androgen deficiency increase risk for osteoporosis, but estrogen may compensate for it, since osteoporosis is not remarkable in patients with androgen resistance. Growth hormone deficiency and hyperprolactinemia are also related to gonadal function and thus bone metabolism.