The role of nucleoside diphospho-sugars in determining the sugar content of surface glycoproteins and glycolipids in mammalian cells will be further explored. Alterations in the nucleotide sugar pools can be achieved by exposure of cells to naturally occurring sugars in lieu of glucose, to sugar analogues or to nucleoside analogues. Sugars and nucleoside analogues are antagonistic in their influence and the implications of the antagonism will be examined in the anti-tumor effectiveness of the nucleoside analogues for P388 cells in the CDF mouse. The utilization of sugars when provided in concert with glucose to Nil Hamster cells and a polyoma-transformed derivative will be examined as will lactate formation and glutamine utilization. ATP metabolism by P388, PyNil and CEM tumor cells will be compared with its metabolism in normal cells in the attempt to clarify striking differences in the ability of the two classes of cells to maintain their ATP upon starvation for glucose.