Metabolic response to fasting is blunted in ucp2−/− mice. Biochemical parameters determined in the plasma of fed and fasted ucp2−/− mice and their wild type (wt) littermates (n = 4 to 10) include (A) insulin, (B) glucose, (C) free fatty acids (FFA), (E) total triacylglycerols (TAG), and (F) β-hydroxybutyrate (BHA). White bars, wild type mice; black bars, ucp2−/− mice. Error bars denote SE. *, Significantly different from wild type (P < 0.05). (D) Immunoblot analysis of phosphorylated hormone-sensitive lipase (p-HSL) levels in epididymal fat pad of fed and fasted (24h) ucp2−/− mice and their wild type littermates. Beta-actin served as loading control.