Effect of vitamin A supplementation on BAT-UCP1 protein levels in lean and obese rats. Five-month-old male lean (A) and obese (B) rats were fed vitamin A at a dose of 2.6 (I), 26 (II), 52 (III) and 129 (IV) mg/kg diet for a period of 20 weeks. Representative western blot showing the levels of UCP1 in BAT of lean and obese rats supplemented with various doses of vitamin A. Equal loading of the protein was ensured by staining the membranes with Ponceau S (image not shown). Bar graph shows the densitometric analysis of 3 rats, representing each of the dietary group. Bars are mean ± SE and are expressed relative to the mean value of lean control group (AI), which was set as 1. a-d Bars not sharing a common superscript are significantly different by one-way ANOVA and LSD post hoc comparison (P < 0.05).