Relationship between changes in plasma gastrin and lower oesophageal sphincter pressure after meals.

Changes in plasma gastrin and lower oesophageal sphincter pressure were measured in 20 subjects after a standard protein meal. Significant increases in both gastrin and sphincter pressure were seen. Peak gastrin response occurred an average of 19-5 minutes and peak lower oesophageal sphincter response 40-0 minutes after the meal. Both gastrin and sphincter pressure showed a wide spectrum of response. In 5 subjects there was no appreciable rise (less than 5 pg/ml) in plasma gastrin after the meal, and 3 of these had symptoms of oesophageal reflux. In this group there was only a small but nervertheless significant rise in lower oesophageal sphincter pressure (mean pressure rise 18-0 per cent of fasting value, p less than 0.05). Greater increases in sphincter pressure (mean rise 54-2 per cent, p less than 0.005) were seen in subjects with a moderate (up to 50 pg/ml) rise in plasma gastrin, and those with the most marked gastrin response (less than 50 pg/ml) showed the greatest rise in pressure (mean rise 80-3 per cent, p less than 0.0025). These results suggest that endogenous plasma gastrin is the main stimulus to the rise in lower oesophageal sphincter pressure after food. Subjects with a poor gastrin response to the meal have only a small increase in sphincter pressure and as a result may be more liable to develop gastro-oesophageal reflux.