INTERLEUKIN-8 ENHANCES TETRAGASTRIN-STIMULATED ACID-SECRETION IN-VIVO

Recent studies have demonstrated a relationship between cytokines and gastric acid secretion. However, details of the mechanism underlying t hat relationship have not been elucidated. For this study, an in vivo experiment was undertaken to investigate the possibility that IL-8 wou ld be involved in the mechanism of gastric acid secretion. Gastric lum en-perfused rats were prepared and the stomachs were perfused with a s aline solution. The effluent was collected at 15-min intervals and ass ayed for titratable acid against 0.01 M NaOH. IL-8 (200 ng/rat) given intravenously did not influence basal acid output in rats. However, wh en IL-8 was administered by injection during continuous tetragastrin i nfusion (4 mu g/kg/hr) acid output increased significantly (P < 0.01). The acid output during the first hour following IL-8 injection was 43 .6% higher than prior to the injection. Acid output during the second hour was lower than during the first hour. However, successive injecti on of IL-8 again increased tetragastrin-stimulated acid output by 23.4 % (P < 0.05). IL-8 injection did not change histamine-stimulated acid output. The results indicate that IL-8 has the effect of enhancing gas trin-stimulated acid secretion and might have an important role in the pathophysiology of gastric acid secretion in vivo.