HIGH-LEVELS OF FERRITIN AND ITS IRON IN FETAL BOVINE SERUM

In 13 lots of the commercial fetal bovine sera, the ferritin levels ra nged between 0.8 and 6.0 mu g/ml. The serum ferritin iron concentratio n as measured by a quantitative immunoprecipitation technique ranged f rom 0.16 to 0.96 mu g/ml, and the iron content of ferritin was about 2 0% regardless of its protein concentration in sera. The percentage of ferritin iron to total serum iron ranged from 8.8 to 28.5%, and correl ated significantly with ferritin concentration (r = 0.9368, P < 0.001) . No significant proportion of the ferritin in fetal serum bound to co ncanavalin A. Immunoblotting showed that the molecular weights of L(iv er)- and H(eart)type subunits of fetal serum ferritin were identical t o those of L and H subunits of adult bovine spleen ferritin (L:21kDa, H:18kDa), respectively, and that the L subunit predominated in the ser um protein. Serum transferrin level was relatively constant (1.8-2.2 m g/ml), whereas transferrin saturation varied from 54.8 to 91.7%. There was a significant correlation between serum ferritin concentration an d transferrin saturation (r = 0.8864, P < 0.001). These findings demon strate that the bovine fetuses have the elevated iron stores. (C) 1997 Elsevier Science Inc.