Abstract: | Phospholipid metabolism of 3T3 mouse fibroblasts has been studied after serum stimulation of arrested cells.The study of 32Pi]incorporation shows : a) in the case of PE and PC an early peak of incorporation in the Gl phase of the cell cycle, 6 hours after serum addition ; b) in the case of PI an intense initial increasing of the incorporation which continues up to a S phase peak.The study of the disappearance of 32P] Phosphate from the different phospholipids points out : a) at the beginning of serum stimulation, an intense breakdown of PI, that continues through the Gl and S phases. Except at the onset, the breakdown of PI, is at any time exactly compensated for by synthesis : the two phenomena are closely linked ; b) a synthesis of PE, from PC probably, at the Gl phase, 4 hours after the serum addition and the beginning of the chase experiment. |