Stimulatory effect of beta-alanyl-L-histidinato zinc on alkaline phosphatase activity in bone tissues from elderly rats: comparison with zinc sulfate action.

The capability of beta-alanyl-L-histidinato zinc (AHZ) to increase alkaline phosphatase activity in the femoral diaphysis from elderly rats was investigated. The femoral-diaphyseal tissues were removed from weanling (3-week-old) and elderly (10-month-old) female rats. Bone tissues were cultured in Dulbecco's modified Eagle medium (high glucose, 4.5%) supplemented with antibiotics and bovine serum albumin. Among various other bone-stimulating factors (AHZ; 10(-5) M, zinc sulfate; 10(-4) M, sodium fluoride; 10(-3) M, insulin; 10(-8) M, and beta-estradiol; 10(-9) M), AHZ had a potent effect on increasing alkaline phosphatase activity in the diaphyseal tissues from both rat groups. In the bone tissues from elderly rats, the effect was concentration dependent (10(-7) - 10(-5) M). At 10(-5) M the effect of AHZ was seen for a longer time during 72-h culture, although the zinc sulfate (10(-5) M) effect was no longer. The effect of AHZ to increase bone alkaline phosphatase activity was completely abolished by the presence of cycloheximide (10(-6) M). AHZ thus appears able to directly stimulate alkaline phosphatase activity dependent on protein synthesis in the bone tissues from elderly rats.