title: Presence of 3-hydroxyanthranilic acid in rat tissues and evidence for its production from anthranilic acid in the brain.
abstract: As assessed by HPLC with electrochemical detection, 3-hydroxyanthranilic acid (3-HANA) was found to be present in the rat brain and peripheral organs. The highest concentrations were measured in the kidney (86 fmol/mg of tissue) and spleen (56 fmol/mg of tissue), whereas the adrenal gland, liver, heart, and several forebrain areas (hippocampus, striatum, parietal cortex, thalamus, amygdala/pyriform cortex, and frontal cortex) contained less 3-HANA (between 15 and 22 fmol/mg of tissue). Slightly lower concentrations of 3-HANA were found in the brainstem and the cerebellum. The metabolic disposition of 3-HANA was examined in tissue slices which were incubated in Krebs-Ringer buffer at 37 degrees C in vitro. Incubation for up to 2 h did not affect 3-HANA concentration in brain tissue. However, inhibition of 3-HANA degradation by the specific 3-hydroxyanthranilic acid oxygenase blocker 4-chloro-3-hydroxyanthranilic acid (4-Cl-3-HANA; 10 microM) resulted in a rapid (within 2.5 min) doubling of 3-HANA levels in slices from cerebral cortex. No further increases were observed after incubations of up to 120 min. Exposure of cortical slices to 3-HANA's putative bioprecursors, 3-hydroxykynurenine (3-HK) and anthranilic acid (ANA), in the absence of 4-Cl-3-HANA resulted in rapid, transient increases in 3-HANA production. Maximal 3-HANA synthesis from ANA exceeded the maximal effect of 3-HK by approximately 11-fold.2+ In the presence of 4-Cl-3-HANA, 1 mM ANA produced 9.0 +/- 0.3 and 89.0 +/- 9.3 (5 min) or 51.6 +/- 7.9 and 187.5 +/- 11.2 (120 min) fmol of newly synthesized 3-HANA/mg of brain tissue, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore 21228.
authors.forename: H
authors.initials: H
authors.lastname: Baran
authors.forename: R
authors.initials: R
authors.lastname: Schwarcz
mesh_terms: D015095:3-Hydroxyanthranilic Acid / Q000031:analogs & derivatives / Q000032:analysis* / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry; D002540:Cerebral Cortex / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D007668:Kidney / Q000032:analysis; D007700:Kinetics; D008297:Male; D010088:Oxidoreductases / Q000037:antagonists & inhibitors; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000032:analysis; D014018:Tissue Distribution; D062367:ortho-Aminobenzoates / Q000032:analysis* / Q000378:metabolism*
chemical_list: D062367:ortho-Aminobenzoates; C031385:anthranilic acid; D015095:3-Hydroxyanthranilic Acid; C026381:4-chloro-3-hydroxyanthranilic acid; D010088:Oxidoreductases; C026382:3-hydroxyanthranilic acid oxidase