Fe isotopes of high specific activity (59Fe and 55Fe) were used as
intrinsic markers of heme Fe (NEN Life Science Products, Inc., Boston),
which were injected into the marginal ear vein of five male
New Zealand rabbits aged 5 mo and 3 kg of weight (37 MBq 59Fe diluted in 0.1 mL of a solution of 9 g NaCl/L), and into the jugular
vein of two male Holstein Friesian calves aged 4 mo and
130 kg of weight (740 MBq 55Fe diluted in 3 mL of a solution of
9 g NaCl/L). Fifteen days after the injection of the isotopes, the rabbits
and calves received an overdose of anesthetic (10% thiopental
at 25 mg/kg I.V); followed by exsanguinations via the jugular route
(Hubrecht & Kirkwood, 2010). The blood of the rabbits and calves
was received in containers with 0.11 M sodium citrate in a ratio
of 9:1 (v/v) citrate:blood and transferred immediately to the laboratory
for processing. Heme Fe compounds were prepared using
rabbit and calf blood.