title: Porphyrin profiles in blood and urine as a biomarker for exposure to various arsenic species.
abstract: A sensitive method using HPLC with fluorescence detection has been established for the measurement of porphyrins in biological materials. The assay recoveries were 88.0+/-1.8% for protoporphyrin IX in the blood, and ranged from 98.3+/-2.7% to 111.1+/-7.4% for various porphyrins in the urine. This method was employed to investigate the altered porphyrin profiles in rats after a single dose of various arsenicals including soluble sodium arsenate and sodium arsenite, and the relatively insoluble calcium arsenite, calcium arsenate and arsenic-contaminated soils at dose rates of 5 mg/kg or 0.5 mg/kg body weight. Porphyrin concentrations increased within 2448 hr after the arsenic treatment in blood and urine. Protoporphyrin IX is the predominant porphyrin in the blood. In rats administered 5 mg As(III)/kg body weight, protoporphyrin IX concentration elevated to 123% of the control values in rats, 24 hr after the treatment. Higher increases were recorded in the urinary protoporphyrin IX (253% at 24 hr; 397% on day 2), uroporphyrin (121% at 24 hr; 208% on day 2) and coproporphyrin III (391% at 24 hr; 304% on day 2), while there was no significant increase (109% on day 3) observed in the urinary coproporphyrin I excretion. In rats administered 5 mg As(V)/kg, urinary excretion of protoporphyrin LX, uroporphyrin, coproporphyrin III and coproporphyrin I elevated to the maximum levels by 48 hr with the corresponding percentage values compared to the control being 177%, 158%, 224% and 143%, respectively. In rats dosed with 5 mg As(III)/kg, the increases (expressed as % of the control values) of protoporphyrin IX in the blood were in the order: sodium arsenite (144%) > sodium arsenate (125%) > calcium arsenite (123%) > calcium arsenate. In contrast, there was no significant increase of protoporphyrin IX, when the six arsenic-contaminated cattle dip soils and nine copper chrome arsenate (CCA-contaminated) soils were administered to the rats. Probable explanations are discussed.
authors.affiliation: National Research Centre for Environmental Toxicology, Brisbane, Queensland, Australia. j.ng@mailbox.uq.edu.au
authors.forename: Jack C
authors.initials: JC
authors.lastname: Ng
authors.forename: Lixia
authors.initials: L
authors.lastname: Qi
authors.forename: Michael R
authors.initials: MR
authors.lastname: Moore
mesh_terms: D000818:Animals; D001152:Arsenicals / Q000008:administration & dosage / Q000494:pharmacology*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000592:standards; D004781:Environmental Exposure; D015386:Hazardous Substances / Q000494:pharmacology*; D007700:Kinetics; D011166:Porphyrins / Q000097:blood* / Q000652:urine*; D011524:Protoporphyrins / Q000097:blood / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000494:pharmacology
chemical_list: D001152:Arsenicals; D015415:Biomarkers; D015386:Hazardous Substances; D011166:Porphyrins; D011524:Protoporphyrins; D012989:Soil Pollutants; C028025:protoporphyrin IX