Real-time RT-PCR analysis confirms the microarray analysis of increased expression of chymotrypsin upon developmental Pb exposure. Relative gene expression in the spleen was determined for control (n=3) and 0.1mM Pb-exposed mouse pups (n=3) representative of separate litters. The TaqMan method was performed as described in the methods. Relative gene expression was calculated with respect to the Ct for the gene normalized to gapdh, as described in the methods. Gene IDs indicate the following: Jarid1a, jumonji; Ctrc, chymotrypsin C; and Mst1r, macrophage stimulating 1 receptor. Significance of the difference between the groups, indicated by the asterisk was determined by the Student’s t-test at p ≤ 0.05.