Zinc deficiency decreases plasma erythropoietin concentration in rats

In 1985, Paterson and Bettger found hypoplastic hematopoiesis in severely zinc-deficient rats. Therefore, we investigated plasma erythropoietin concentration in zinc-deficient rats. Forty 4-wk-old male Sprague- Dawley rats were assigned into 4 dietary treatment groups of 10 for the 4-wk study: zinc-deficient group (4.5 mg zinc and 35 mg iron/kg; -Zn), iron-deficient group (30 mg zinc/kg, no supplemental iron; -Fe), zinc/ iron-deficient group (4.5 mg zinc/kg, no supplemental iron; -Zn-Fe), and control group (AIN-93G; Cont). Water intake determined at d 19 was similar among all treatment groups. At d 27-28, bioimpedance was measured. The intracellular water/extracellular water ratio was significantly increased in the -Zn group (p < 0.05). Compared to the Cont, group, the plasma erythropoietin concentration was increased by iron deficiency and decreased by zinc deficiency (p < 0.01). Hematocrit was significantly decreased in both the -Fe and -Zn-Fe groups and was significantly increased in the -Zn group (p < 0.01). Transferrin saturation in the -Fe and -Zn-Fe groups was significantly lower than the Cont group (p < 0.01), and that of the -Zn group was highest among all groups. The low plasma erythropoietin concentration might account for depressed hematopoiesis associated with zinc deficiency.