A comparison of iron induction of rat lymphocyte ferritin synthesis in vivo and in vitro

1. 1. Administration of increasing amounts of iron to rats in vivo induced both liver and peripheral blood lymphocyte ferritin synthesis measured in vitro. 2. 2. Incubation of liver and lymphocytes with increasing concentrations of iron in vitro stimulated liver, but not lymphocyte ferritin synthesis. Exposure of lymphocytes to iron invitro produced only slight depression of ferritin and total protein synthesis and no appreciable change in cell viability compared to controls. 3. 3. Incubation of lymphocytes with ⁵⁹Fe-citrate in vitro resulted in continuous uptake and incorporation of labelled iron into both ferritin and total cell protein during 24 hr. 4. 4. These data suggest that induction of lymphocyte ferritin synthesis observed after iron administration in vivo resulted from secondary stimulatory mechanisms rather than due to iron per se.