Correlation of the effect of feeding upon the cell cycle distribution profiles of MPC-11 cells with the relative appearance of [3H]-choline labeled material in microsomal subfractions and other cell fractions.

Cultures of mouse plasmacytoma cells (MPC-11) grown within the range 6-23 x 10(5) cells/ml showed considerable variation in cell cycle distribution profiles and also differences with regard to relative amounts of microsomal subfractions. The variability of appearance of heavy rough (HR) and light rough (LR) microsomal subfractions was not merely due to differences in nutritional state of the culture. Cultures containing a high S/G2 + M cell cycld distribution ratio showed a high content of HR microsomal membranes; as the S/G2 + M ratio decreased, so too decreased the amount of HR material whilst the amount of LR microsomal membranes increased. The results indicate that there is a direct correlation between phase of cell cycle and both amount and relative distribution of rough microsomal membranes, the smooth fraction (S), however, remains relatively unchanged.