In this study, the effects of dexamethasone, retinoic acid and vitamin D on the transdifferentiation of adipocyte and osteoblast were investigated using 3T3-L1 and KS483 cells, pre-adipocyte and pre-osteoblast cell lines, respectively.

Both cells were induced to differentiate in adipogenic or osteogenic conditions for 10 days, and the enzyme activities of lipoprotein lipase (LPL) and alkaline phosphatase (AP), well-known marker enzymes for adipogenesis and osteogenesis, respectively, were determined. Oil red-O and the AP activity staining of the cells were also determined.

The presence of dexamethasone during the differentiation period did not cause any specific alterations in the LPL on AP activities in either cell line. Retinoic acid increased AP activity in both cell lines, whereas no change was observed in LPL activity in 3T3-L1 cells. Vitamin D increased AP activity but decreased LPL activity in 3T3-L1 cells.

The fates of both cell lines in differentiation lineage have been already determined. However, the presence of retinoic acid and vitamin D during the differentiation period can cause the transdifferentiation of both committed cell lines.