Anabolic effect of phosphogenistein and phosphodaidzein on bone components in rat femoral-metaphyseal tissues in vitro.

Abstract

The effect of phosphogenistein and phosphodaidzein, which are phosphorylated for the hydroxyl group (OH) at the 7-position of genistein and daidzein, on bone components was investigated. Femoral-metaphyseal tissues obtained from male rats (4 weeks old) were cultured for 24-72 h in Dulbecco's modified Eagle's medium (high glucose, 4.5%) supplemented with antibiotics and bovine serum albumin. The presence of phosphogenistein (10(-5) M) caused a significant increase in calcium content, alkaline phosphatase activity, and deoxyribonucleic acid (DNA) content in bone tissues cultured for 24 h. Phosphodaidzein (10(-5) M) significantly elevated bone calcium and DNA content. These effects were completely prevented by the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis. When femoral-metaphyseal tissues were cultured for 48 h in the presence of parathyroid hormone (1-34) (PTH; 10(-8) M) or prostaglandin E2 (PGE2; 10(-6) M), bone calcium content was significantly decreased. This decrease was significantly blocked by the presence of phosphogenistein (10(-6) and 10(-5) M) or phosphodaidzein (10(-6) and 10(-5) M). The presence of PTH (10(-8) M) or PGE2 (10(-6) M) caused a significant increase in glucose consumption and lactic acid production by bone tissues. These increases were significantly inhibited by the presence of phosphogenistein (10(-5) M) or phosphodaidzein (10(-5) M), indicating their inhibitory effect on bone resorption. The present study has demonstrated that both phosphogenistein and phosphodaidzein have an anabolic effect on bone metabolism in rat femoral-metaphyseal tissues in vitro.