Effect of prenatal exposure to isoflavones on bone metabolism in mice at adulthood.

Early postnatal exposure to genistein resulted in improved bone health at early adulthood in mice. The objective of the present study was to determine whether in utero exposure to isoflavones also has a positive effect on bone health, resulting in higher bone mineral density (BMD) and greater resistance to fracture at adulthood. Pregnant mice received daily subcutaneous injections of genistein (3.75 mg), daidzein (3.75 mg), genistein (3.75 mg) + daidzein (3.75 mg), or vehicle from d 9 to 21 of pregnancy. At birth, offspring (n = 12/group/gender) remained with their respective mother and were weaned at postnatal age of 21 d and fed control diet, devoid of isoflavones, until 4 mo of age, at which time tissues were collected. There was an overall effect of treatment on femur BMD, which was higher (p<0.001) among control and genistein groups compared with daidzein and genistein + daidzein groups. Treatment did not have a significant effect on femur peak load. Among females, daidzein resulted in a lower (p=0.02) BMD of lumbar vertebra (LV) 1-4 than all other groups however peak load of LV4 did not differ due to treatment or gender. In conclusion, in utero exposure to isoflavones did not result in functional benefits to bone at young adulthood.