Effect of Carbachol on Vascular and Luminal Release of Immunoreactive Gastrin from Isolated Perfused Rat Duodenum

The release of intestinal gastrin was examinedusing the isolated vascularly and luminally perfused ratduodenum. Results show that duodenal gastrin wasreleased into both the intestinal lumen and circulation. The basal release of immunoreactive gastrin(IRG) into the lumen was 23.3 ± 1.8 pg/min andthat into the vasculature was 70.1 ± 8.2 pg/min.The administration of 1 M carbachol into thevascular perfusate resulted in a marked reduction of luminalrelease of IRG; however, vascular release of IRG was notaffected. The carbacholinduced inhibition of luminalrelease of IRG was blocked by atropine but not by hexamethonium. These data suggest that only theluminal release of IRG from the rat duodenum, but notvascular release of IRG, is under the inhibitory controlof the cholinergic muscarinic mechanism.