Adrenalectomy reverses pre-existing obesity in adult genetically obese (ob/ob) mice.

Objective: To determine if adrenalectomy would reverse the pre-existing gross obesity, characteristic of adult genetically obese (ob/ob) mice.

Design: Adult (12 week old) female ob/ob mice were adrenalectomized and fed a stock diet for 6 or 14 weeks. They were housed at 23-25 degrees C or 33 degrees C. Food intake and total body energy were determined.

Results: Adrenalectomy abolished the hyperphagia characteristic of ob/ob mice. Adrenalectomized ob/ob mice consumed 8-17% less food than intact lean mice. Adrenalectomized ob/ob mice housed at 23-25 degrees C lost 55% of their pre-existing body energy within 6 weeks after surgery and 75% of their body energy within 14 weeks after surgery. At 14 weeks after surgery, body weights and body energy content of the adrenalectomized ob/ob mice were comparable with values for intact lean mice. Intact ob/ob mice pair-fed to adrenalectomized ob/ob mice lost only half as much body energy as the adrenalectomized ob/ob mice did, indicating that adrenalectomy not only diminished food intake in ob/ob mice but also increased their energy expenditure per unit food consumed. Adrenalectomized ob/ob mice housed at 33 degrees C lost only half as much body energy in 6 weeks as did mice housed at 23-25 degrees C.

Conclusion: Adrenalectomy reverses the gross obesity characteristic of adult ob/ob mice by abolishing their hyperphagia and increasing their energy expenditure per unit food consumed.