Effects of Ehrlich Ascites Tumor on Iron Incorporation into Heme*

The Ehrlich ascites tumor takes up intravenous Fe 59 and utilizes much of this for cellular heme formation. In vivo experiments showed tha t the amount of iron utilized by liver and marrow for heme synthesis was directly related to the amount of iron taken up by these tissues. In vitro experiments revealed no difference in iron-protoporphyrin chelation by liver mitochondria from control and tumor-bearing mice. There was likewise no evidence of insufficient iron for heme synthesis in these mitochondria. Large injections of iron had no effect on liver catalase activity in control or tumor-bearing mice. I t was concluded that any decrease in liver heme synthesis due to a tumor could possibly be related to a decreased ~-aminolevulinic acid dehydrase activity but not to any effect at the site of iron-protoporphyrin chelation.