Distribution of ferrochelatase activity in density gradient separated bone marrow cells.

A simple, reproducible, and economical procedure for separating bone marrow cells into distinct populations and stages of maturation was developed and used to investigate the distribution of ferrochelatase activity in rat bone marrow cells. Density gradient ultracentrifugation of normal rat marrows on discontinuous arabinogalactan layers of 16.5-30.0% resulted in six distinct fractions enriched for myeloblasts, neutrophils, pronormoblasts, normoblasts, or lymphocytes. Segregation reflecting different stages of cell development was demonstrated. Neutrophils appeared at a greater density and were clearly separated from precursor myeloblasts. Normoblasts appeared at a greater density and were clearly separated from precursor pronormoblasts. Lymphocyte distribution within the gradient followed a normal curve (P < 0.05). A single gradient layer which consisted of greater than 80% lymphocytes was shown to be associated with significantly increased (P < 0.05) ferrochelatase specific activity (units/mg protein); the remaining cell populations did not differ significantly from each other in specific activity.