Calcium transport and adenosine triphosphatase activities of erythrocyte membranes in congenital spherocytosis

Abstract

Calcium transport from red cells was measured in seventeen patients with congenital or hereditary spherocytosis (HS). The efflux remained at a lower level in resealed ghost cells of patients than in normal cells both in the presence and absence of adenosine triphosphate (ATP). We studied the activities of Ca²⁺, Mg²⁺-ATPase, ouabain-sensitive Na⁺, K⁺-ATPase, Mg²⁺-ATPase and Ca²⁺-(spectrin-)ATPase in cell membranes prepared by washing the cells with hypotonic medium. The mean ±SD Ca²⁺, Mg²⁺-ATPase/Mg²⁺-ATPase of HS patients was 3.34 ± 1.06, and 2.81 ± 0.42 in control subjects. Na⁺, K⁺-ATPase/Mg²⁺-ATPase was 2.38 ± 0.38 in HS cells compared to 2.01 ± 0.41 in normal cells. Ca²⁺-ATPase/Mg²⁺-ATPase of HS membranes was 0.57 ± 0.18 and the control value 0.43 ± 0.08. These data indicate calcium retention in the erythrocytes of HS patients in spite of increases in Ca²⁺, Mg²⁺-ATPase activity in the majority of patients.

Key Words:

• spherocytosis
• red cell membrane
• calcium
• ATPase