The effect of pH on the metabolism of rabbit bone marrow.

In 1924 Warburg and coworkers (1) reported that variation in both the pH and the bicarbonate concentration of the medium affected the anaerobic glycolysis of Flexner-Jobling rat carcinoma in vitro. When the bicarbonate level was held constant, an increase in COz tension was accompanied by a fall in the rate of anaerobic glycolysis. At a constant pH, increasing the bicarbonate concentration from 3.1 to 15.5 milliioles per liter was associated with a progressive increase in the rate of anaerobic glycolysis; further increase in bicarbonate concentration produced no significant effect. Craig and Beecher (2) demonstrated that lowering the pH from 7.48 to 7.18 in a bicarbonate-containing medium depressed aerobic glycolysis of rat retina without significa,nt alteration in oxygen consumption. At a constant pH, aerobic glycolysis was increased with increasing COz tensions from 1 to 5 volumes per cent. Similar effects have been reported for the aerobic glycolysis of cat cortex and medulla (3). Warren (4) reported that the presence of bicarbonate resulted in a 20 to 40 per cent increase in the oxygen consumption of rabbit bone marrow. The work of Summerson, Gilder, and Lee’ on the effects of pH and bicarbonate on the in vitro metabolism of mouse lymphosarcoma prompted parallel studies on normal rabbit bone marrow, which according to Warren (5) exhibits metabolic characteristics approaching those of tumor tissues. An attempt was made to answer the following questions. What are the metabolic characteristics of normal bone marrow at various ranges of pH? Is the metabolism at a given pH influenced by changes in bicarbonate concentration? Can the respiratory metabolism be accounted for in terms of glucose utilization? What fraction of the total aerobic acid production is represented by lactic acid? Can differences be found between the metabolism of bone marrow cells and the cells of lymphosarcoma?