Glutathione peroxidase and selenium deficiency in patients receiving home parenteral nutrition: time course for development of deficiency and repletion of enzyme activity in plasma and blood cells.

The time course for the depletion of red blood cell (RBC) and plasma glutathione peroxidase (GSHPx) activity in five patients receiving home parenteral nutrition was documented. During the development of the RBC GSHPx deficiency, enzymatic activity and protein content decreased. Plasma and RBC selenium content were similarly decreased as was cellular metabolism of exogenous hydrogen peroxide. When the replacement of Se (selenious acid) began, there was a rapid increase (within 6 h) in plasma GSHPx activity. Platelet and granulocyte (PMN) GSHPx activity, which were low when Se replacement began, became normal within a time consistent with the kinetics of platelet and PMN production. RBC GSHPx did not become normal for 3-4 mo. This is consistent with the time course for RBC production. It appears that the repletion of blood cell GSHPx requires the formation of these cells in the presence of Se.