Relationship between vitamin A and iron in the liver.

Anemia associated with vitamin A deficiency and increased liver iron has implicated vitamin A in the regulation of iron release from the liver. To study this relationship further, groups of weanling rats were fed diets as follows: low iron/low vitamin A, low iron/high vitamin A, normal iron/normal vitamin A, high iron/low vitamin A and high iron/high vitamin A. After 6 weeks the animals were killed, and blood and liver samples were taken for analyses of hemoglobin, hematocrit, red blood cell count, serum and liver vitamin A, serum and liver iron and total iron-binding capacity. Low dietary iron, but not low vitamin A intake, affected hemoglobin, hematocrit and red blood cell counts but not serum vitamin A levels. Mean serum vitamin A levels were not significantly lower in groups fed high dietary iron. High dietary iron was also associated with lower mean liver vitamin A levels; these differences were statistically significant only for the low vitamin A diet group. A high vitamin A intake was associated with a significantly lower mean hepatic iron level for the high dietary iron intake group. These data support the hypothesis that vitamin A is involved in the regulation of iron release from the liver.