Interactions of human organic anion transporter 1 (hOAT1) with substances associated with forensic toxicology

Renal excretion is an important elimination pathway for substances associated with forensic toxicology, such as medicines, agricultural chemicals, and industrial chemicals. This study aimed to elucidate the renal elimination pathway of substances using culture cells stably expressing the human organic anion transporter 1 (hOAT1) gene. Substances tested were diazepam, triazolam, haloperidol, amitriptyline, mianserin, bromovalerylurea, phenobarbital, acetaminophen, acetylsalicylic acid, lidocaine, aconitine, atropine, caffeine, nicotine, malathion, dichlorvos, fenitrothion, chlorpyrifosmethyl, paraquat, diquat, potassium cyanide, sodium arsenite, sodium azide, o-cresol, and probenecid (control, a representative inhibitor of hOAT1). Results demonstrated that diazepam, triazolam, amitriptyline, mianserin, malathion, fenitrothion, chlorpyrifosmethyl, and probenecid significantly inhibited representative substrates of hOAT1 and para-aminohippuric acid uptake by hOAT1. IC50 values of the aforementioned substances were 133.3, 185.2, 354.1, 312.6, 114.2, 26.6, 191.5, and 7.9 μM, respectively. Ki values were 83.5, 86.0, 573.9, 99.0, 134.0, 51.2, 324.6, and 9.1 μM, respectively. In conclusion, the current results suggest that fenitrothion and chlorpyrifosmethyl are transported with pharmacokinetics indicative of hOAT1 involvement in the human kidney.