From Jackson Labs: Mice homozygous for the obese spontaneous mutation, Lepob (commonly referred to as ob or ob/ob), exhibit obesity, hyperphagia, transient hyperglycemia, glucose intolerance, and elevated plasma insulin. They are also hypometabolic, hypothermic, and subfertile. Wound healing is impaired and hormone production from both pituitary and adrenal glands is increased. This strain is used to model phases I and II of diabetes type II and obesity. Obesity is characterized by an increase in the number and size of adipocytes. Although hyperphagia contributes to the obesity, homozygotes gain excess weight and deposit excess fat even when restricted to a diet sufficient for normal weight maintenance in lean mice.