GZMK and Hypertension: GRK2 is expressed in peripheral blood mononuclear cells and lymphocytes.7, 62 GRK activity and GRK2 expression are increased in lymphocytes of hypertensive humans and experimental models of hypertension.60, 63, 64 Lymphocyte GRK2 mRNA expression directly correlates with systolic blood pressure and plasma norepinephrine levels.64 GRK2 in lymphocytes is elevated >30% among persons with systolic blood pressure >130 mm Hg.