CARNOSINE AS STIMULATOR OF CYTOSTATIC AND PHAGOCYTIC FUNCTIONS OF PERITONEAL-MACROPHAGES

Biochemical changes were studied in murine C3HA peritoneal macrophages with special reference to their cytostatic and phagocytic functions after a single intraperitoneal injection of carnosine or 4-methyluracil (0.45 mM solutions) or peptone. Within a day after injection, carnosine and 4-methyluracil activated adenosine deaminase and purine nucleoside phosphorylase, the key enzymes of purine catabolism, which is a major source of O2-. in macrophages. In carnosine-stimulated macrophages, the activity of membrane AMP 5'-nucleotidase decreased from the first to third day, indicating a decrease in the inhibiting influences of adenosine on the cells and an activation of macrophages. Carnosine activated the cytostatic and phagocytic functions of macrophages associated with production of O2-.. The stimulating effect of carnosine on macrophages is possibly mediated by specific receptors on the plasma membrane of the cells.