Urinary excretion of 5-hydroxyindole-3-acetic acid and 5-hydroxytryptophol after oral loading with serotonin

Life Sci. 1992;50(17):1207-13. doi: 10.1016/0024-3205(92)90320-o.


The urinary excretion patterns of the serotonin (5-hydroxytryptamine; 5-HT) metabolites 5-hydroxyindole-3-acetic acid (5-HIAA) and 5-hydroxytryptophol (5-HTOL) were examined after ingestion of bananas, a food rich in 5-HT. The bananas contained on an average 25 micrograms 5-HT/g pulp. Both urinary 5-HIAA and 5-HTOL increased markedly (15- to 30-fold) shortly after eating 3-4 bananas, with the highest concentrations found in urine specimens collected after 2-4 h, and did not return to normal until after 8-10 h. The excretion of 5-HIAA increased from a control mean value of 3.9 mg/24 h to 12.7 mg/24 h, when conventional diets were supplemented with 3-4 bananas. The corresponding results for 5-HTOL were 16.8 micrograms/24 h and 60.7 micrograms/24 h, respectively. Of the banana-derived 5-HT ingested, 60-80% was recovered in the urine as 5-HIAA and only 0.3-0.5% as 5-HTOL. However, since both the time-course and relative increase in 5-HTOL was similar to that of 5-HIAA, there was no effect on the urinary 5-HTOL to 5-HIAA ratio. By contrast, acute alcohol consumption produced a considerable elevation of this ratio.

MeSH terms

  • Administration, Oral
  • Adult
  • Alcohol Drinking
  • Chromatography, High Pressure Liquid
  • Diet
  • Female
  • Fruit / chemistry
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Hydroxyindoleacetic Acid / urine*
  • Hydroxytryptophol / urine*
  • Male
  • Serotonin / pharmacokinetics*


  • Hydroxytryptophol
  • Serotonin
  • Hydroxyindoleacetic Acid