Western Blot of Lewis (L), Fischer (F) and Buffalo (B) rat plasma HK. Blood was collected into sodium citrate (see “Materials and methods”) from each of the rat species. An aliquot was added to a customized LDS-PAGE plasma sample buffer containing reducing agent (see “Materials and methods”). After electrophoresis, blotting, and blocking, the blot was probed using an IgG rabbit antirat HK polyclonal antibody and detected using a goat antirabbit IgG alkaline phosphatase conjugate and BCIP/NBT. A specific band at 110 kDa was observed representing rat HK in the plasma. A nonspecific band at 68 kDa is an artifact of the assay dye reacting with blotted rat albumin.