FIG. 6.

Spleen, thymus, and liver weights depicted as milligrams per gram body weight (BW). Wet weights (N ≥ 10 per group) were recorded at three postnatal time points. In this and subsequent panels, weights from PCB-treated animals of all four genotypes were compared with weights from corn oil–treated B6 controls at the same ages. Interindividual and group statistics are available upon request. (Top row) There were no significant differences in spleen weights at PND6. At PND13, spleen weights were significantly decreased in Ahr^b1_Cyp1a2(−/−) pups. At PND28, spleen weights were significantly decreased in Ahr^b1_Cyp1a2(+/+) pups. (Middle row) At PND6, there were significant decreases in thymus weights in Ahr^b1-containing mice. At PND13, thymus wet weights were significantly decreased in all genotypes, but the greatest decrease was seen in Ahr^b1-containing pups. At PND28, thymus wet weights were significantly decreased only in Ahr^b1_Cyp1a2(+/+) pups. (Bottom row) At PND6, there were significant increases in liver weight in all PCB-treated groups compared with controls. At PND13, liver weights were only increased in Ahr^b1-containing pups. At PND28, liver weights were increased significantly only in Ahr^b1_Cyp1a2(−/−) pups. Liver histology showed no differences in any of the genotypes throughout this time period (data not shown).