Turnover of 5-Hydroxytryptamine (Serotonin) in Tissues. ∗

Abstract

Summary

Using tryptophan-C¹⁴ and 5-hydroxytryptophan-C¹⁴ it has been possible to measure turnover of serotonin in a number of tissues in the rabbit. The measured half lives are: platelets and spleen, 33-48 hours; stomach, 17 hours; intestine, 11 hours. Although amounts of serotonin in brain were too small to permit isotopic measurement it was possible to estimate its turnover from the increase following administration of harmaline, an inhibitor of serotonin metabolism. Such estimates indicate a half-life in brain of the order of minutes.