Lung and liver weights in newborn C3H/HeN pups. Pups were exposed to 1, 3, 7, or 14 d of RA (white hatched bars) or >95% O2 (gray bars). Pups were killed at the designated times. Total lung and liver weights were recorded (A and C). Ratios of lung weight/body weight and liver weight/body weight were calculated (B and D). Results are reported as mean ± SEM and data were assessed by two-way ANOVA with modified t test posthoc for individual differences, n = 10 to 18, p < 0.05. An effect of day was observed on lung weights and lung weight/body weight ratios. An effect of day, an effect of exposure, and an interaction were observed on liver weights with an effect of day on the liver weight/body weight ratios. *Indicates different from same day RA.