Human buccal epithelial cells as a potential biochemical predictor of essential hypertension: identification of key cellular processes.

1. Human cheek cell Na+/H+ antiporter activity (measured as the rate of proton-dependent 22Na+ uptake) was determined in seven normotensive (NT) and four hypertensive (HT) subjects following preincubation of cheek cells with a low molecular weight fraction isolated from NT saliva together with the ionophore, nigericin. 2. Cheek cells preincubated in this manner exhibited greater Na+/H+ antiporter activity with the mean values being 4.2 nmol Na+.mg protein.5 min for the NT group and 1.7 for the HT group. 3. It is possible that stimulation of Na+ transport is due to cellular accumulation of K+ ions during preincubation which, in the presence of the K+/H+ selective ionophore, nigericin, can cause cellular reacidification promoting further 22Na+ uptake via the Na+/H+ antiporter.