Prediction of stroke lesions in stroke-prone spontaneously hypertensive rats by glutathione peroxidase in erythrocytes.

The incipient timing of cerebral strokes in the stroke-prone spontaneously hypertensive rats (SHRSP) was biochemically determined by investigating the relationship between the glutathione peroxidase (GSH-Px) activity in erythrocytes and the extent of stroke lesions. When the blood pressure of SHRSPs was maintained at over 240 mmHg, the GSH-Px activity fell, and the body weight also decreased. In SHRSP whose GSH-Px activity in erythrocytes had dropped below 23 units/ml of blood, the incidence of cerebral strokes was 98% (n = 88/90). The hematocrit level did not change even after the GSH-Px activity had dropped to 23 units/ml of blood. The reduced GSH-Px activity in erythrocytes observed during continued hypertension was found to be due to a decrease in GSH-Px protein, and not to any inactivation of the enzyme, as evident from immunochemical titration. At the moment when the GSH-Px activity had dropped to 23 units/ml of blood, and the control diet was changed to one based on fish or a hydralazine treatment given, the activity recovered, and an increase in body weight and prolongation of the life-span were observed. It was deduced from these findings that tracing the GSH-Px activity in erythrocytes in SHRSP would serve as an indicator for predicting and prognosing stroke lesions.