Observations on the Release and Turnover Rate of 5-Hydroxytryptamine in the Gastrointestinal Tract

Abstract

AbstractThree groups of experiments were carried out on man, dogs and rabbits to strengthen the theory of the intestinal origin of blood 5-hydroxy-tryptamine (5-HT) and urinary 5-hydroxyindoleacetic acid (5-HIAA), and to contribute to the solution of the problem of the turnover rate of 5-HT in the gastrointestinal mucosa. Serum obtained from blood taken by catheterisation from the hepatic veins contained, in man and dogs, more 5-HT than serum obtained from vena cava blood. Moreover, dogs deprived operatively of the entire gastrointestinal tract presented a sharp drop in the urinary 5-HIAA excretion. It was tentatively calculated, from the data gathered in this study, that half-life of gastrointestinal 5-HT is approximately 6 to 8 hours in dogs, and 7 to 12 hours in man.