ERYTHROCYTIC PROTEIN-KINASE-C ACTIVITY IN PRIMARY HYPERTENSION

Objectives. Increased protein kinase C activity has been reported in e rythrocytes from patients with primary hypertension and also from hype rtensive rats. In this phenomenological study, we investigated whether a possible increased activity was the result of an augmented amount o f enzyme molecules or a mere active enzyme, Design. Collect blood samp les. separate erythrocytes from other blood cells. After partial purif ication of protein kinase C in the erythrocyte lysate, assay the enzym e activity under optimal conditions using a specific peptide substrate . Setting. Central Hospital in Eskilstuna and University Hospital in U ppsala, Sweden, Subjects. Healthy individuals: 47 persons (20 women an d 27 men). Ten patients with untreated primary hypertension. Main outc ome measures, Erythrocytes were separated from leucocytes and platelet s by passing through a cellulose column followed by repeated washings, Some proteins in the erythrocyte lysate interfering with protein kina se C assay were removed by chromatography on DEAE-cellulose. Results. The mean protein kinase C activity in erythrocytes from healthy indivi duals was 0.18 +/- 0.02 pmol [P-32]phosphate min(-1) x 10(6) cells, re gardless of sex and age, The corresponding value for patients with pri mary hypertension was 0.16 +/- 0.04 pmol [P-32]phosphate min(-1) X 10( 6) cells, Conclusions. The amount of protein kinase C, measured as the activity at optimal assay conditions, in erythrocytes from patients w ith primary hypertension is not critical for the development of modera te hypertension.