title: [First-pass metabolism of acetaminophen in thyroxine treated rats].
abstract: The study on the first-pass metabolism of acetaminophen was carried out in normal and thyroxine-treated rats, administered 30 mg/kg by three routes of intravenous, intraperitoneal, and oral one. Unconjugated acetaminophen and two major metabolites, glucuronide and sulfate in the plasma and urine were then measured 5 and 24 h after the administration, respectively. It was found that there was no difference in total percentage of excreted amount, independent of the routes for administration, between normal and thyroxine-treated rats. This fact shows that acetaminophen is absorbed completely from the gastrointestinal tract. However, it was also found that the extraction ratio of gastrointestinal tract in thyroxine-treated rats became smaller, and that the volume of distribution and total body clearance became larger than those in normal rats. The first-pass metabolism of acetaminophen was found to be influenced by the continuous administration of thyroxine.
authors.affiliation: Department of Hospital Pharmacy, Toyama Medical and Pharmaceutical University, Japan.
authors.forename: C Y
authors.initials: CY
authors.lastname: Zhu
authors.forename: J
authors.initials: J
authors.lastname: Hirate
authors.forename: I
authors.initials: I
authors.lastname: Kanamoto
authors.forename: T
authors.initials: T
authors.lastname: Nakagawa
authors.forename: I
authors.initials: I
authors.lastname: Adachi
authors.forename: I
authors.initials: I
authors.lastname: Horikoshi
authors.forename: V O
authors.initials: VO
authors.lastname: Bhargava
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000284:Administration, Oral; D000818:Animals; D004347:Drug Interactions; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013974:Thyroxine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000082:Acetaminophen; D013974:Thyroxine