Totally isolated whole porcine stomachs, perfused extracorporeally with homologous blood, were used for recording gastric electrical and mechanical activity. Hormones Hormones were administered into the arterial system of the isolated organ. Pentagastrin, methacholine and electrical stimulation of the vagus nerve induced premature control potentials with uncoupling of the normal, phase-locked, pattern of electrical control activity and also produced electrical response activity and mechanical reaction. When glucagon was infused a progressive decrease of frequency of the cycles of electrical control activity was observed. Glucagon also abolished electrical response activity and mechanical activity, if they were present prior to hormone infusion. When pentagastrin, methacholine or electrical stimulation were applied during the infusion of glucagon, the responses to these stimulants were decreased or absent. The inhibitory action of glucagon was dependent on the duration of infusion of this hormone and lasted for 30-45 min after the infusion was discontinued. During infusion of glucagon the mean gastric arterial perfusion pressure and gastric peripheral vascular resistance were reduced.