The fate of 5-hydroxytryptamine in the lungs

Abstract

Abstract Isolated guinea-pig lungs perfused with Krebs solution were found to remove 5-hydroxytryptamine (5HT) from the fluid perfusing them. Two processes were involved: (1) the active uptake of 5HT by cells in the lungs, and (2) the metabolism of 5HT to 5-hydroxyindole-acetic acid (5HIAA). The experiments emphasize that the lungs have a metabolic capacity in addition to their passive function of gas diffusion. Derangement of the metabolic functions of the lungs may prove to be as serious clinically as derangement of their respiratory functions. Failure to clear the venous plasma of free 5HT would affect the aggregation of platelets and might thus have a bearing on the problem of deep venous thrombosis in man.