The Effect of Sex Difference on Iron Exchange in the Rat

Summary.When compared with normal males, female Wistar rats have significantly higher serum iron levels, a higher rate of plasma iron turnover and a higher proportion of their plasma iron is diverted into non‐erythroid tissues. These difference are abolished by castration and reestablished by the supplementation of testosterone and oestrogen to castrated animals. The effect of sex hormones on iron handling is independent of their action on erythropoiesis, since in hypertransfused animals with complete inhibition of erythropoiesis the sex difference in serum iron levels and in hepatic iron uptake is maintained, The absolute rate of iron absorption is similar in both groups, but when the daily absorption of food iron is related to growth rate, it is considerably higher in females than in males (P< 0.001). The cumulative effect of a relatively higher iron absorption in females is the establishment of large iron stores which by virtue of their higher rate of exchange with transferrin contribute to their higher plasma iron turnover.