Relationship between erythrocytes glutathione peroxidase and incidence of stroke lesion in the stroke-prone spontaneously hypertensive rat.

1. To determine biochemically the incipient timing of cerebral stroke in stroke-prone spontaneously hypertensive rats (SHRSP) the relation between the glutathione peroxidase (GSH-Px) activity in erythrocytes and the extent of stroke lesion was investigated. 2. When the blood pressure of SHRSP was maintained over 250 mmHg, the GSH-Px activity was lowered and the body weight also decreased. In the SHRSP where the GSH-Px activity in erythrocytes dropped below 23 units/mL blood, the incidence of cerebral stroke was 98% (n = 88/90). 3. The haemoglobin and haematocrit level were unchanged even after the GSH-Px activity dropped to 23 units/mL blood. 4. Lowering of GSH-Px activity in erythrocytes observed during continued hypertension was found to be due to decreased GSH-Px protein, but not to an inactivation of enzymes, as evidenced from immunochemical titration. 5. Lowering of GSH-Px activity in erythrocytes was found to be closely related with the incidence of cerebral stroke in SHRSP. These findings suggest that tracing of the GSH-Px activity in erythrocytes in SHRSP may serve as an indicator for prediction and prognosis of stroke lesion.