The effect of beta-alanyl-L-histidinato zinc (AHZ) on bone cell function was investigated in osteoblastic MC3T3-E1 cells. Cells were cultured for 3 days at 37 degrees C in a CO2 incubator in plastic dishes containing alpha-modified minimum essential medium supplemented with 10% fetal bovine serum. After the cultures, the medium was exchanged for that containing 0.1% bovine serum albumin plus AHZ (10(-7)-10(-5) M) or other reagents, and the cells were cultured further for appropriate periods of time. The presence of AHZ (10(-7)-10(-5) M) produced a remarkable increase of alkaline phosphatase activity and protein concentration in osteoblastic cells. Thus increase were seen with the prolonged cultivation (12-21 days). With the culture of 1, 3 and 12 days, the effect of AHZ (10(-6) M) to increase alkaline phosphatase activity and protein concentration was more intensive than the effect of zinc sulfate (10(-6) M). The AHZ effects were completely abolished by the presence of cycloheximide (10(-6) M), indicating that AHZ stimulates protein synthesis in the cells. The present study suggests that AHZ has a stimulatory effect on cell differentiation, and that this effect is partly involved on protein synthesis in osteoblastic cells.