Figure 4

The relative quantification (mean ± standard deviation) of osteocalcin (a) and osteopontin (b) transcripts as measured by real-time RT-PCR in calvarial osteoblasts taken from newborn control rats and those exposed to various concentrations of caffeine during pregnancy and subsequently cultured in osteogenic differentiation medium for 7, 14 or 21 days. *p <0.05, **p < 0.01, ***p < 0.001.