IN VIVO STUDIES OF 5-HYDROXYINDOLE METABOLISM IN PATIENTS WITH HEPATIC CIRRHOSIS AND IN RATS*†

Open Access
Publisher Website
Google Scholar
Abstract
5-Hydroxyindole metabolism in patients with hepatic cirrhosis was studied by determining the urinary excretion of 5-hydroxyindole-acetic acid (5-HIAA) following the intravenous administration of 0.6 mg/kg of 5-hydroxytryptophan (5-HTP). In 20 patients with decompen-sated hepatic cirrhosis the recovery of administered 5-HTP as urinary 5-HIAA was significantly (p < 0.001) greater 62 [plus or minus] 19.2%) than among 21 control subjects (32 + 5.3%) and among 7 subjects with extrahepatic obstruction (31 [plus or minus] 14.0%). When 1 gAg sodium orthoaminobenzoic acid was administered to rats intraperitoneally the recovery of intra-peritoneally administered 5-HTP in doses of 50 mg/kg as urinary 5-HIAA was significantly (p < 0.001) greater than in rats receiving 5-HTP together with NaCl. The results indirectly support the concept that serotonin (5-HTA) conjugation may occur in the liver and that when 5-HTA conjugation is impaired more 5-HTA may be available for metabolism to 5-HIAA.