In investigations with various groups of patients there was no correlation between fasting serum IRG levels and LES pressures in individual subjects with undisturbed or disturbed sphincters. After food ingestion a short phase of LES pressure increase (from 13.5 ± 1.5 to 21.7 ± 3.8 mm Hg) could be observed. This peak occurs during the phase of rise in gastrin level, but there was no correlation between IRG levels and LES pressure in individual cases. In patients with gastroesophageal reflux we can demonstrate a diminished release of gastrin after a test meal, but there was also a diminished capacity of the LES. In conclusion, in this investigation it has not been possible to show a clear connection in humans between serum IRG and LES functio