Increased protein kinase C activity has been reported in erythrocytes from patients with primary hypertension and also from hypertensive rats. In this phenomenological study, we investigated whether a possible increased activity was the result of an augmented amount of enzyme molecules or a more active enzyme.Design.
Collect blood samples, separate erythrocytes from other blood cells. After partial purification of protein kinase C in the erythrocyte lysate, assay the enzyme activity under optimal conditions using a specific peptide substrate.Setting.
Central Hospital in Eskilstuna and University Hospital in Uppsala, Sweden.Subjects.
Healthy individuals: 47 persons (20 women and 27 men). Ten patients with untreated primary hypertension.Main outcome measures.
Erythrocytes were separated from leucocytes and platelets by passing through a cellulose column followed by repeated washings. Some proteins in the erythrocyte lysate interfering with protein kinase C assay were removed by chromatography on DEAE-cellulose.Results.
The mean protein kinase C activity in erythrocytes from healthy individuals was 0.18 ± 0.02 pmol [32P]phosphate min−1 × 106 cells, regardless of sex and age. The corresponding value for patients with primary hypertension was 0.16 ± 0.04 pmol [32P]phosphate min−1 × 106 cells.Conclusions.
The amount of protein kinase C, measured as the activity at optimal assay conditions, in erythrocytes from patients with primary hypertension is not critical for the development of moderate hypertension.