Use of the intact mouse skeletal-muscle preparation for metabolic studies. Evaluation of the model.

1. We examined the isolated mouse skeletal-muscle model in vitro, commonly used by many investigators, for its suitability for metabolic studies. 2. Despite the fact that pH, O2 saturation, osmolality and the release of the enzyme creatine kinase remained stable, histochemical studies showed large cores devoid of glycogen, suggesting that the incubated muscle had lost its viability. 3. This study indicates that caution should be exercised when interpreting the results of studies with intact isolated mouse muscles.