Changes of erythropoietin concentrations in plasma and kidney induced by zinc deficiency in rats

Abstract

Some researchers reported that oral zinc (Zn) effectively cured iron refractory anemia. We reported before that Zn deficiency depressed plasma erythropoietin (EPO) concentration in rats. We propose a hypothesis that Zn deficiency depresses EPO production in kidney. To test the hypothesis, thirty 3‐week‐old male SD rats were assigned into 3 groups of 10 for the 4‐week study receiving AIN‐93G‐based EDTA‐treated casein diet: ad libitum fed control group (AIN‐93G), moderate Zn‐deficient group (4.5 mg Zn/kg diet) and pair‐fed group (AIN‐93G). Plasma and kidney (medulla and cortex) EPO concentrations were measured using ELISA kit. Difference between groups was statistically analyzed by Fisher's PLSD. P value less than 0.05 was considered significant. Plasma EPO concentration of Zn‐deficient group was significantly decreased compared with control group, and pair‐fed group was marginally decreased compared with control group (P=0.056). Kidney medulla EPO concentration was decreased in Zn‐deficient group compared with pair‐fed group. Kidney medulla EPO concentration in pair‐fed group was higher than that of control group but the difference was not significant. No significant difference was observed in kidney cortex EPO concentration. These results support the hypothesis that Zn deficiency impairs EPO production in kidney.This work was supported by Japan Society for the Promotion of Science Young Scientists (Start‐up) (21800073).