Basal hyperchlorhydria and its relation to the plasma concentrations of secretin, vasoactive intestinal polypeptide (VIP) and gastrin during prolonged strain.

Twenty young men divided into two groups participated in a five day training course with prolonged and heavy physical exercise, calorie supply deficiency and severe sleep deprivation. Basal acid output (BAO) was measured immediately after the course in seven of ten subjects who were given placebo tablets (placebo group) and in four of ten subjects who had a daily intake of 1 g cimetidine (cimetidine-group) during the course. Median BAO increased 3-fold in the placebo subjects (from 2.7 mmol/h to 8.2 mmol/h) but showed no increase in the cimetidine treated subjects. The median fasting plasma concentrations of secretin increased 2-8-fold during the course. Gastric suction for 1 h or ingestion of cimetidine reduced the plasma concentration of secretin by approx. 50%. Vasoactive intestinal polypeptide (VIP) increased 2-fold and was not influenced by reduction of gastric acid. The placebo group showed a small increase (P less than 0.05) in plasma concentration of gastrin on day two during the course. The study shows a marked hyperchlorhydria which partly explains the fasting hypersecretinemia found during prolonged strain. This strain-induced hyperchlorhydria could be abolished by treatment with the selective H2-receptor antagonist cimetidine.