Differential biosynthesis of proteins in separated gastric mucosal cells

Rat gastric mucosal cells were separated according to size by rate-zonal sedimentation through a medium containing a gradient of bovine albumin. Numbers and mean sizes of cells indicated two main populations, 430-1000 microns 3 and 1500-2500 microns 3, with a discontinuity between 1000 and 1500 microns 3. Gradient fractions, combined into pools of increasing cell size, synthesized radiolabelled proteins which were resolved by electrophoresis, densitometry and computation. The smallest cells (430-800 microns 3) tended to synthesize radiolabelled proteins with the highest relative specific radioactivities. The decrease in relative specific radioactivity with increase in cell size was compatible with a progression from precursor cells towards the more differentiated state.