Effect of plasma from hypertensive subjects on Ca2+ transport in permeabilized human neutrophils.

1. The effects of plasma fractions from essential hypertensive subjects (n = 14) and normotensive subjects (n = 14) on Ca2+ transport in permeabilized human neutrophils was studied using an ion-selective electrode. 2. Plasma fractions were obtained by gel filtration and contained substances with a molecular mass in the range 1000-1500 daltons. This fraction isolated from essential hypertensive subjects has been shown to increase blood pressure after intravenous injection in the rat. 3. The rate of Ca2+ uptake by permeabilized neutrophils after addition of extracellular Ca2+ was significantly accelerated during incubation of the cells with the hypertensive fraction (1049.3 +/- 807.7% vs 242.5 +/- 320.9% of the control value, mean +/- SD, P less than 0.05). 4. It is concluded that the hypertensive plasma fraction increases Ca2+ accumulation in subcellular particles, so that under excitatory conditions Ca2+ release in arterial smooth muscle might be enhanced.