Modulation in the rates of incorporation of lipid precursors during the cell cycle

Abstract

The rates of incorporation of ³H‐choline into phospholipid and of ³H‐fucose into glycolipid have been measured during the cell cycle of the murine mastocytoma, P815Y, synchronized by either velocity sedimentation or excess thymidine blockade. The rate of ³H‐choline incorporation into acid‐insoluble material exhibited two distinct maxima coincident with the early S and G₂ periods, whereas the rate of incorporation of ³H‐fucose into lipid extractable material was maximal during the G₂ period. Variation in rate of incorporation of ³H‐choline could not be accounted for by changes in membrane permeability.