Comparison of oxygen consumption of syndecan-3^–/– and wild-type mice. (A and B) Indirect calorimetry of male (A) and female (B) syndecan-3^–/– mice (n = 4) and wild-type mice (n = 4) on the HF diet. Heat (kcal/h) was measured for 24 hours in an indirect calorimeter. The mean energy expenditure (kcal/h) was calculated separately during the light and dark cycles for each group of mice. Syndecan-3^–/– mice exhibited greater energy expenditure during both the light and dark cycles (*P < 0.001 wild type vs. syndecan-3^–/– for each sex, Student's t test).