Observations on the Nature of the Relationship between Cell Division and Carbohydrate Metabolism

A L T H O U G H there is considerable evidence that carbohydrate metabolism plays an important part in the process of cell division (see Bullough, 1952), conclusions have differed regarding the relative importance of glycolysis and catabolism involving respiration. In the adult mouse epidermis Bullough & Johnson (1951) found that cell division was dependent upon the respiratory oxidation of pyruvate by the tricarboxylic acid cycle. On the other hand, Pomerat & Willmer (1939) showed that, in tissue culture, agents that inhibited respiration had little immediate effect on cell division, while Laser (1933) found that growth of cultured fibroblasts could continue when respiration was greatly diminished by low oxygen tensions. Further, Warburg (1930) concluded that cell growth is associated with glycolysis. A similar difference in the relationship of mitotic activity to the respiratory and glycolytic forms of carbohydrate metabolism was indicated by changes occurring in the midbrain and the red-blood cells of the chicken embryo during embryonic development. In the midbrain (O'Connor, 1950a) there was a corresponding decrease in the number of dividing cells in a unit volume of tissue and in the rate of aerobic glycolysis as measured by the production of acid by midbrain tissue isolated in a glucose containing medium x(acid formation did not occur when glucose was omitted from the medium; O'Connor, 1949). Under these conditions the rate of respiration remained constant. Since the respiratory quotient was unity, this constant rate of respiration was taken to indicate a constant rate of glucose utilization by respiratory metabolism. Further investigations (O'Connor, 1950ft) showed that, when the rate of aerobic glycolysis of the isolated midbrain was decreased by fluoride or iodoacetate, cell division was inhibited by concentrations which did not diminish the rate of respiration nor alter the respiratory quotient. Thus it was concluded that, in the midbrain, cell division was dependent on aerobic glycolysis, as measured by the acid production of the isolated tissue in a glucose-containing medium.