Stimulatory effect of blood platelet factor(s) on glycolysis in cell cultures

The addition of bovine blood platelet homogenate to confluent cultures of three established mouse cell lines (L-929, Balb c/3T3 and SC) brings about a rapid increase of lactic acid formation. Homogenates prepared from quiescent cells previously treated with platelet breakdown products show an increased rate of glycolysis as compared with homogenates of nonstimulated cell cultures. Activities of hexokinase, pyruvate kinase and lactate dehydrogenase remained unaltered but the activity of phosphofructokinase increased by about 60 per cent. Transport of 2-deoxy-D-glucose into the cells was slightly stimulated. It is concluded that the transport of glucose was not a limiting factor in confluent 3T3 cells. The findings suggest that the increase of phosphofructokinase activity may have accounted for the changes in glycolysis seen in intact cells and cell-free homogenates prepared from cultures exposed to some unknown factor(s) present in platelet homogenate.