Nonheme iron mobilization from the liver in piglets.

Abstract

An experiment was conducted with 38 piglets to clarify relationships ofhepatic xanthine oxidase and plasma ferroxidase to storage iron mobilization. In conjunc-tion with the result of hypotransferremia, hepatic xanthine oxidase and plasma ferroxidasewere extremely low at birth. Accordingly, it seems likely that due to these enzymatic andprotein deficits, the rate of iron storage cells to plasma iron transfer may be quite limited, if at all. When there were sudden increases in plasma transferrin, ferroxidase activity andhepatic xanthine oxidase after piglets had utilized colostrum, a corresponding increase iniron release from the liver was observed. It is possible that the ferrous to ferric cycles inthe liver and plasma are activated by the increase in iron-releasing enzymes and plasmatransferrin, and that thereafter the rate of transport of iron from storage cell to erythro-poietic organ is accelerated still more.Eventually, as a result of storage iron depletion, plasma iron and hemoglobin levelsdecreased and overt iron deficiency appeared markedly from 3 days of age onward.. Milkferroxidase and transferrin showed a high level at farrowing and decreased progressivelyto 10 days postpartum. Although plasma ferroxidase increased intensively after pigletshad absorbed colostrum, the amount of colostral ferroxidase absorbed by piglets was verysmall, as compared with that derived from endogenous sources after the cessation of theabsorption of colostral protein by the piglets.