Relation between the osmolality trend and ornithynedecarboxylase activity in red blood cells of uremie patients during hemodialytic treatment

In uremie patients during chronic hemodialysis an increase in the volume of red blood cells is observed. Contemporaneously there is an increase in intraerythrocytic ornithynedecarboxylase activity beyond the normal content (P< 0.01), a high level of seric and plasmatic polyamines (P< 0.01) and a decrease in seric osmolality (P< 0.01) with pH improvement. The trends of osmolality, ornithynedecarboxylase, mean cell volume and pH are significantly related. Our data support the hypothesis that, during hemodialysis, red blood cell volume changes and increased ornithynedecarboxylase activity are dependent on the general improvement of plasma tonicity. Moreover, the absence of inhibition of ornithynedecarboxylase activity by high levels of putrescine is noted. © 1998 Elsevier, Paris.