Platelet serotonin 5-HT2A receptor binding in patients with carcinoid tumor
2004 (English)In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, Vol. 64, no 1, 3-8 p.Article in journal (Refereed) Published
Background: As carcinoid tumors produce and secrete serotonin, various serotonin markers in blood, plasma and urine have been used as diagnostic tools, and quantification of the urinary excretion of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) is the method most frequently used.
Methods: [ 3 H]lysergic acid diethylamide ([ 3 H]LSD) binding to the platelet serotonin 5-HT 2A receptor was investigated in nine patients with carcinoid tumors. The possible effect of serotonin-rich food on the receptor binding was also investigated.
Results: B max for [ 3 H]LSD binding was significantly lower in the carcinoid group than in the control group (mean±SD: 17.6±1.3 vs. 23.9±5.2 fmol/mg protein; p=0.007). K d for [ 3 H]LSD binding was significantly higher in the carcinoid group than in the control group (median: 1.14 vs. 0.71 nmol/L; p=0.03). B max was inversely related to the urinary 5-HIAA excretion, but the correlation did not reach statistical significance (r s =-0.57; p=0.14). Intake of five bananas per day for one week had no effect on B max or K d in healthy volunteers.
Conclusions: The results are consistent with a down-regulation of the 5-HT 2A receptor as a response to the high serotonin levels found in patients with carcinoid tumors. Intake of serotonin-rich food does not affect the receptor characteristics. Further studies are needed to determine whether the platelet 5-HT 2A receptor status can be used as a supplement to urinary 5-HIAA and other biochemical variables in carcinoid tumors.
Place, publisher, year, edition, pages
Oslo: Taylor & Francis , 2004. Vol. 64, no 1, 3-8 p.
Aged, Blood Platelets/drug effects/*metabolism, Carcinoid Tumor/*diagnosis/metabolism, Down-Regulation, Female, Humans, Hydroxyindoleacetic Acid/metabolism/urine, Lysergic Acid Diethylamide/metabolism/pharmacology, Male, Middle Aged, Musa/chemistry, Receptor; Serotonin; 5-HT2A/blood/*metabolism, Serotonin/*metabolism, Tumor Markers; Biological/urine
IdentifiersURN: urn:nbn:se:umu:diva-6044PubMedID: 15025423OAI: oai:DiVA.org:umu-6044DiVA: diva2:145712