The effect of epinephrine on the plasma gastrin level was investigated in three patients with Zollinger-Ellison syndrome (ZES) and in 14 normal subjects. Two ZES patients had undergone total gastrectomy, and the third had undergone subtotal gastrectomy before our study. A significant increase in plasma gastrin, from 23 +/- 5 pg/ml to 53 +/- 20 pg/ml, in response to intravenous epinephrine (40 ng/kg.min), was observed in the normal subjects. This response was completely abolished by beta-blockade. In the ZES patients, epinephrine (40 ng/kg.min) also resulted in an increase in the plasma concentration of gastrin. The basal and maximum concentrations of gastrin were 580 and 1680 pg/ml in patient 1, 145000 and 320000 pg/ml in patient 2, and 200 and 1800 pg/ml in patient 3, respectively. beta-Adrenergic blockade suppressed the epinephrine-stimulated gastrin release in these patients as well. Graded intravenous doses of epinephrine given to the ZES patients resulted in elevation of the plasma gastrin in a dose-dependent manner. Insulin hypoglycemia caused an increase in both plasma epinephrine and plasma gastrin in ZES patients and normal subjects. A significant correlation between plasma gastrin and epinephrine during insulin hypoglycemia was observed in both groups. Exercise, with use of a bicycle ergometer, resulted in an increase in plasma epinephrine. An increase in plasma gastrin with exercise was observed in the ZES patients, and this was also suppressed by beta-blockade. The results suggest that gastrinoma cells, like normal G cells, are equipped with beta-adrenergic receptors that regulate gastrin release.