Iron Deficiency: Impaired Liver Growth and DNA Synthesis in the Rat

S ummary . This study deals with liver growth and DNA synthesis in young, rapidly growing rats weaned to an iron deficient diet. Shortly after the development of anaemia there was a depression in the rate of liver growth that was more profound than that of body growth. The rate of increase in total liver DNA was similarly depressed, in comparison with iron-supplemented animals. Paradoxically, in the deficient rats, two normally sensitive indices of DNA synthesis, incorporation of [³H]thymidine into DNA and activity of thymidine kinase, were unaffected. This was also the case in animals acclimated to a 4 hr/day restricted feeding regimen in order to control for possible variations in feeding patterns. Although [³H]thymidine incorporation was normal throughout a 24 hr period, incorporation of ³²P into liver DNA was depressed in the iron deficient rats. The results indicate changes in liver DNA synthesis due to iron deficiency that are distinct from those seen in starvation and protein-calorie malnutrition. Probably DNA synthesis in iron deficiency is modified through a depression of de novo synthesis, in the presence of normal salvage pathway activity.