Injection of soluble Fet3p increases transferrin saturation in aceruloplasminemic mice. Both normal mice (Cp⁺/Cp⁺) and mice with a targeted deletion in the ceruloplasmin gene (Cp^-/Cp^-) were bled via daily phlebotomy, and plasma iron and transferrin saturation was measured. Aceruloplasminemic (Cp^-/Cp^-) mice were injected on day 8 with heat-denatured Fet3p (HD Fet3). On day 9, the same mice were injected with active Fet3p, and blood samples were obtained 1 hour later and transferrin saturation determined (mean and standard deviation).