Mean total (unesterified + esterified) retinol concentration in liver, lungs, and plasma of control, VA-, and VARA-supplemented neonatal rats on day 1 after dosing on postnatal day 4. Each bar represents the mean ± SEM of n = 42 (control), n = 24 (VA) or n = 18 (VARA) rats. P < 0.05 (ANOVA): VA or VARA vs. other. VA, vitamin A, VARA, VA combined with retinoic acid.