serotoninleveransen

Serotoninleveransen refers to the hepatic handling of serotonin as it arrives in the liver, including uptake, metabolism, and clearance from the bloodstream. In humans, peripheral serotonin is predominantly produced in the enterochromaffin cells of the gut and released into the portal venous system, delivering serotonin directly to the liver before it reaches systemic circulation. Bloodborne serotonin is also carried by platelets, which sequester serotonin and release it at sites of tissue injury; however, platelets do not supply the liver directly.

Within hepatocytes, serotonin is taken up by liver cells, a process that involves monoamine oxidase A (MAO-A) and, in some pathways, other cellular transporters. MAO-A catalyzes oxidative deamination of serotonin to 5-hydroxyindoleacetaldehyde, which is further oxidized to 5-hydroxyindoleacetic acid (5-HIAA). The liver can conjugate metabolites, and 5-HIAA is ultimately excreted in the urine; some metabolites may be excreted into bile.

The liver therefore acts as a major sink for circulating serotonin, contributing to first-pass metabolism and helping regulate systemic serotonin levels. Serotoninleveransen can be influenced by liver state: hepatic impairment or portosystemic shunting common in advanced liver disease can reduce hepatic clearance, potentially altering peripheral serotonin tone and related physiological effects such as vascular tone and gut motility. Research in this area uses isolated hepatocytes, perfused liver models, and measurement of 5-HIAA in urine or plasma.

Overall, serotoninleveransen describes the liver’s role in trapping and metabolizing circulating serotonin, shaping its systemic availability and effects.