The relationship of purine metabolism to the macrophage-mediated increase of high energy phosphates in skeletal muscle

Previous investigations have demonstrated that the high energy phosphate and adenine nucleotide content of wounded tissue are decreased. Purine metabolism was investigated in incubated λ-carrageenan wounded skeletal muscle and in muscle exposed to peritoneal macrophages or macrophage-conditioned media. Wounded muscle released predominately uric acid into the incubation medium; whereas, nonwounded muscle released inosine, hypoxanthine, and xanthine as well as uric acid. Macrophages incubated with nonwounded muscle changed the purine release pattern toward one of wounded muscle. The conversion of inosine to allantoin and uric acid by macrophages increased linearly with the addition of up to 1 × 10 7 macrophages per incubation. Muscles incubated in macrophage-conditioned media had a decreased release of inosine and hypoxanthine and higher tissue levels of creatine phosphate, ATP, ADP, AMP, and adenosine compared to muscles incubated in standard media. These data suggest that the macrophage determines the pattern of purine release from wounded skeletal muscle in the incubated system and that in conditioned media a high energy phosphate promoting factor may exert its effect by mechanisms that augment the adenine purine pool.