Release of gastrin on vagal stimulation in the cat.

Gastrin released by electrical vagal stimulation was measured in the portal blood of eviscerated cats. Blood flow was recorded by a drop chamber technique and the total gastrin output calculated. Basal peripheral gastrin levels averaged 65 pg/ml and basal portal levels 225 pg/ml. On unilateral vagal stimulation with frequencies above 3-4 Hz gastrin release rapidly increased, reaching a peak within 5-10 min. In spite of continued stimulation and independent of frequency, the gastrin levels declined and returned to basal values after a total of 2-3 000 stimuli. A new maximal response could be induced first after a recovery period of 15-30 min. In the same cat stimulation of either the left or the right vagus released equal maximal amounts of gastrin (average 32 000 pg). The maximal gastrin output on vagal stimulation corresponds to less than 1% of the total content of antral gastrin determined with radioimmunoassay.