Effect of postoperative nutrition on muscle high energy phosphates

This study examines the effect of hypocaloric nutritional regimens on muscle high energy phosphates in normal subjects and patients following total hip replacement. Eighteen patients undergoing total hip replacement and 11 normal subjects on a four-day period of bedrest were studied. The patients were randomly assigned to receive either: (1) 90 gms/day glucose; (2) 70 gms/day amino acids; or (3) 90 gms/day glucose + 70 gms/day amino acids. A percutaneous muscle biopsy was performed before operation and on the morning of the fourth day after operation. Samples were analyzed for adenine triphosphate (ATP), adenine diphosphate (ADP), adenine monophosphate (AMP), phosphocreatine (PC), free creatine (CR), lactate, and pyruvate. Normal subjects were assigned to receive either: (1) 90 gms/day glucose; (2) 70 gms/day amino acids; or (3) no caloric intake. The patients receiving amino acid alone demonstrated a decrease in ATP, ADP, and PC, while AMP and free creatine rose. No significant changes were seen in patients who received 90 gms/day glucose either with, or without, amino acids. There were also no significant changes in any of the normal subjects. These results suggest that a series of metabolic changes occur in skeletal muscle following injury such that small amounts of glucose are important for maintenance of cellular energy levels.