Fig. 2.

The development UGT1A6 in the pediatric liver. A, activity toward 100 μM serotonin increased with age. Model returned an activity of 2.560 nmol · min · ⁻¹mg protein⁻¹ at birth and increased to apparent adult activity at 4.737 ± 0.33 nmol · min · ⁻¹mg protein⁻¹ (95% CI, 4.0041–5.434). The 90th percentile of adult activity was reached at 14 months of age (r² = 0.09244, absolute sum of squares = 178.8, Sy.x = 1.993). Each point represents each sample assayed in duplicate. The model is unweighted and constrained by medium convergence criteria requiring five consecutive iterations of the fit to change the sum-of-squares by less than 0.0001%. B, protein levels did not correlate with age. Two-tailed Pearson correlation returned p = 0.8455 and r² = 0.001132. C, protein levels did not correlate with enzyme activity. Two-tailed Pearson correlation returned p = 0.2193 and r² = 0.04403. Band intensities were calculated using ImageJ software (National Institutes of Health) and were normalized to the pooled samples on each Western blot.