The Effect of Secretin on Pepsin Secretion in Heidenhain Pouch

ABSTRACT

PURPOSE: This research was done to confirm the effect of secretin on pepsin secretion and to study whether or not feeding can depress the secretin-stimulated pepsin secretion (SSPS) with its related factors. METHODS: Heidenhain (HP) and Pavlov pouches (PP) were made in 6 dogs and cannulae were then inserted into the pouches. The fluids were collected through the cannula every 10 minutes for 3 hours in various conditions, including resting, feeding, secretin perfusion, acidification of the stom-ach and, gastric distension. A modified Anson's hemoglobin method was used to check the amount of pepsin. RESULTS: When secretin was perfused in the HP, there was no increase of pepsin secretion at 0.1 and 0.2 CU/kg/hr, but the pepsin secretion increased at 0.4 and 1.0 CU/kg/hr. Compared to the control, ANOVA showed significant differences for secretin 0.4 CU/kg/hr (P<0.01) and for secretin 1.0 CU/kg/hr (P<0.001). When milk was administered through the gastric cannula after secretin stimulation, pepsin production increased in the PP, but pepsin secretion in the HP dropped close to the basal level after administering milk. This depression was not related to acidity of the milk. ANOVA showed significant differences for secretin with milk vs milk alone (P<0.0005) and vs secretin alone (P<0.0025). The inhibition of SSPS was not observed with any gastric distension or acid perfusion. CONCLUSION: In the HP, secretin increased the pepsin secretion and the vagus nerve has an inhibitory effect on pepsin secretion under secretin stimulation. Milk feeding depressed the SSPS, and that depression was not related to pH of the food and gastric distension. Further study is needed in order to clarify the mechanism of depression.