Cation Transport in Erythrocytes of Normal and Porphyric Cows: Erythrocyte Membrane Adenosine Triphosphatase Activities

Congenital erythropoietic porphyria is characterized by the increased production of the type I porphyrins due to an enzymatic defect of the erythropoietic tissue. The disease in cattle is characterized by a haemolytic anaemia with a shortened red cell median survival time. The erythrocyte membrane Na-K-ATPase was investigated as a possible focus of an iutracorpuscular defect resulting in a shortened survival of the porphyric erythrocytes. Erythrocytes from porphyric cows had significantly more total, ouabain insensitive, and ouabain sensitive ATPase activity than normal erythrocytes. Erythrocyte ouabain sensitive and. total ATPase activities of the porphyric cows were inversely correlated with the volume percent (PCV) of erythrocytes (r = − 0.96, P < 0.01), haemoglobin concentration (r = − 0.99, P < 0.01), and erythrocyte (RBC) count (r = − 0.99, P < 0.01). Direct correlations were found between porphyric erythrocyte potassium concentrations and ATPase activities. The increased ATPase activities observed for the porphyric cows were concluded to be a function of the shorter average age of the red cell population. Decreased erythrocyte survivability, as reflected in the degree of anaemia, would result in a shorter mean erythrocyte age with the elevated enzyme activities characteristic of young cells.