The serum ferroxidase system and the effect of estrogen on plasma iron

Abstract

Estrogen effects on plasma iron and ferroxidase activity in some mammals and domestic fowl are studied, to investigate a possible estrogen mechanism on iron through its action on the ferroxidase system. Although estrogen generally induces ceruloplasmin, iron mobilization, characterized by a rise in plasma iron, was evident only in rats and chickens. Gonadotrophin treatment confirmed these results. A decreasing affect on plasma iron was noted in rabbits and guinea-pigs, substantiated by some bibliographical data. Ferroxidase activity increased and a copper-dependent factor was evident in copper injected species. Iron mobilization, however, was produced only in rats and chickens. D-penicillamine treatment considerably lowered ferroxidase activity in rats and suppressed the estradiol increasing plasma iron effect. This response to the copper-chelating drug did not take place in the other species. This phenomenon could be explained by the presence of two copper-dependent ferroxidases (ferroxidase I or ceruloplasmin and ferroxidase II) in rat plasma, as recently published.