SOMATOSTATIN EFFECTS ON LOWER ESOPHAGEAL SPHINCTER FUNCTION

The effect of somatostatin (GH-RIH) infusion (2 .mu.g/min) on lower esophageal sphincter pressure (LESP) responses to various stimuli was evaluated in adult male baboons. GH-RIH infusion did not affect basal LESP, but did cuase a significant suppression of mean immunoreactive insulin (IRI) to 5.8% of basal values (P < 0.05). Pentagastrin IV caused dose-related increases in LESP that were unaffected by GH-RIH. Abnormal compression caused a 3-fold rise in LESP (P < 0.005) without and with GH-RIH. Atropine (20 .mu.g/kg i.v. bolus) completely blocked this cholinergic LES pressure response. Intragastric alkali, as well as intragastric glycine, caused significant increases in LESP (P < 0.05). These LESP responses to alkali and to glycine were totally abolished by GH-RIH. GH-RIH infusion in the baboon does not affect basal LESP, LES smooth muscle response to exogenous stimulation or a cholinergically mediated LES response. GH-RIH does inhibit the response of LESP to intragastric alkali and to Gly by the apparent suppression of a hormonally mediated mechanism.