Increased forskolin stimulation of lymphocyte-adenylate cyclase in normotensive subjects predisposed to essential hypertension.

Since a significant heritability has been shown for forskolin stimulation of lymphocyte adenylate cyclase activity in twins, we evaluated lymphocyte forskolin-stimulated adenylate cyclase activity with respect to a familial predisposition towards essential hypertension. Lymphocyte adenylate cyclase activity was measured in broken cell preparations of 32 male normotensive volunteers with (n = 15) and without (n = 17) a positive family history of hypertension. The maximal forskolin stimulation of adenylate cyclase activity was significantly higher in the positive compared with the negative group (maximal stimulation of activity 53.5 +/- 3.4 versus 41.2 +/- 1.9 pmol cyclic AMP (cAMP)/mg protein per min; P less than 0.01). Dose-response curves showed a significantly greater stimulation of adenylate cyclase activity in the positive group at forskolin concentrations of 10(-7) to 2 x 10(-4) mol/l. The median effective dose (ED50) and adenylate cyclase activity in the absence of forskolin were similar in both groups. We conclude that lymphocyte forskolin-stimulated adenylate cyclase activity may depend in part on hereditary factors associated with a familial predisposition to essential hypertension.