Oxygen Consumption and Body Fat Content of Young Lean and Obese (OB/OB) Mice

Abstract

Rates of oxygen consumption were determined daily from birth to 19 days of age and weekly thereafter until 16 weeks of age in lean and obese mice. As early as 5 days after birth obese mice consumed less oxygen than lean mice. Obese mice weighed more than lean mice by 6 days of age and contained 38% more fat than lean mice at 7 days of age. At 14 days of age obese mice contained 53% more fat than lean mice. Beyond 3 weeks of age oxygen consumption of obese mice was less than observed in lean mice when the results were expressed per g body weight, but the values for obese and lean mice were similar when expressed per animal. These results demonstrate that alterations in energy metabolism occur very early in the life of obese mice.