Average expression stability values in osteoblasts, macrophages and osteoclasts and expression profiling of 18S and GAPDH during osteoblast differentiation. qPCR gene expression analyses were carried out on cDNA derived from differentiating osteoblasts, macrophages and osteoclasts. Gene expression data were converted to relative expression using the relationship (E+1)-ΔCT and the data were analyzed using the geNorm algorithm to identify the rank-order of gene expression stabilities in osteoblasts (A), macrophages (B) and osteoclasts (C). Transcript profiling of 18S and GAPDH throughout osteoblast differentiation (D-E). Gene expression data were normalized to the geometric average of ACTB, B2M, HMBS and HPRT1 and are expressed as relative expression to day 1. Data represents mean ± SEM.