Sex- and age-related response to aromatase deficiency in bone

Deficiency of sex steroids causes osteoporosis, but the relationship betwee n estrogen and androgen is not clear because androgen is converted into est rogen by aromatase. In this study, we characterized bone metabolism in the aromatase-deficient (ArKO) mouse. At 9 weeks old, a marked loss of cancello us bone due to increased bone resorption was observed not only in female Ar KO mice but also in males. The degree of bone loss in ArKO males was simila r to that in females, and treatment with 17 beta -estradiol completely rest ored the bone mass in both sexes. At 32 weeks old, female ArKO mice showed severe loss of cancellous and cortical bone. Male ArKO mice df this age als o showed reduced bone mass, but the degree of bone loss in females was more marked than that in males. Here, we report sex- and age-related responses to aromatase deficiency in bone. (C) 2001 Academic Press.