Reports from University of Gottingen advance knowledge in hormones.

According to recent research published in the Journal of Bone and Mineral Metabolism, "The development of bone in immature rats and in aged rats has not been thoroughly studied. Therefore, we investigated the development of bones in young, middleaged, and aged female rats."

"Because most rat chows contain soy proteins, including estrogenic isoflavones, as a source of protein, comparison of effects on mineral density and on areas of the cancellous and cortical parts of the metaphysis of the tibia as measured by quantitative computer tomography in animals fed with soy-free and soy-containing food was made. As surrogate parameters of bone metabolism serum, osteocalcin (OC) and the breakdown products of bone collagen-the Crosslaps-were also determined. The cancellous density increased between day 25 after birth to reach peak bone mass at 90 days of age; in 18-and 20-month-old animals, significant reduction was observed that was more profound in the animals fed with soy-free food. Serum OC and the Crosslaps were highest in 15-day-old and lowest in 9-, 18-, and 20-month-old animals. Animals fed with soy-containing food had significantly higher osteocalcin levels at day 15 and at 9 and 18 months of age. In the aged animals, intake of soy isoflavones that have an estrogenic effect appears to exert beneficial effects as these aged animals lost less cancellous bone, as indicated by their surrogate parameters of metabolism in the serum. It is concluded that ...