Effects of adrenalectomy on energy balance of obese mice are diet dependent.

Obese (ob/ob) and lean mice were adrenalectomized at 3 or 6 wk of age and fed a high-carbohydrate stock diet or a high-fat semipurified diet for 3 wk. Adrenalectomy of obese mice fed the stock diet reduced the energy intake, energy gain, and efficiency of energy retention so that the values equaled those of lean mice. Hindlimb muscle gain of adrenalectomized obese mice fed the stock diet increased by 50-100%, and concentrations of plasma insulin were reduced so that they also approached values in lean mice. In contrast to results obtained when the stock diet was fed, adrenalectomy of obese mice fed the high-fat diet resulted in only slight reductions in energy intake, energy gain, or efficiency of energy retention. Likewise, muscle gain was not improved nor were plasma insulin concentrations decreased when adrenalectomized obese mice were fed the high-fat diet. Although adrenal secretions contribute substantially to the gross obesity that develops in ob/ob mice fed the stock diet, these secretions are unnecessary for development of obesity in ob/ob mice fed the high-fat diet. Factors other than adrenal secretions per se, which are influenced by diet composition, thus mediate development of obesity in ob/ob mice.