"In osteoporosis, you have more resorption than formation," Wiren said.
Aging, glucocorticoid therapy for asthma, alcoholism, chronic smoking and bone marrow malignancies are believed to cause androgen deficiency. All in addition to reduced hormone secretion from the testes, a condition called hypogonadism are associated with osteoporosis development in men.
The disease also is a side effect of androgen deprivation therapy, a common treatment for prostate cancer that wipes out most male hormones found in the body.
"Women and estrogen have been targets for a lot of osteoporosis research because estrogen is effective at stopping bone loss," Wiren said. "We understand a lot more about estrogen than we do androgen. But both genders have androgen and both genders have estrogen and both are at risk for the development of osteoporosis. It's also clear in intervention studies that you can effectively treat osteoporotic women with androgen."
One option being studied for treating osteoporosis in men and women is androgen therapy, either through androgen replacement using hormone drugs, or androgen replacement combined with estrogen replacement.
"You get a better response with combined treatment than with either steroid alone, which suggests they're doing different things," Wiren said.
Selective androgen receptor modulators, or SARMs, are among a class of drugs that also are being studied as an alternative to androgen therapy. Like selective estrogen receptor modulators, SARMs activate the hormone's signaling pathway, but only in a tissue-specific manner. By targeting androgen receptors in bone, SARMs are thought to curb potential risks for prostate cancer progression and other side effects that can result from androgen replacement.
Contact: Jonathan Modie
Oregon Health & Science University