title: Effects of azathioprine, 6-mercaptopurine, and 6-thioguanine on canine primary hepatocytes.
abstract: OBJECTIVE
  To investigate the cytotoxic effects of azathioprine, 6-mercaptopurine, and 6-thioguanine on canine hepatocytes.
  
  
  METHODS
  Commercially available cryopreserved canine primary hepatocytes.
  
  
  METHODS
  The study consisted of 2 trials. In trial 1, hepatocytes were incubated with azathioprine, 6-mercaptopurine, or 6-thioguanine at 1 of 6 concentrations (0.468, 0.937, 1.875, 3.750, 7.500, or 15.000 μmol/L) for 24, 48, or 72 hours. At each time, cell viability and lactate dehydrogenase (LDH) activity were determined for each thiopurine-concentration combination, and alanine aminotransferase (ALT) activity was determined for cells incubated with each thiopurine at a concentration of 15 μmol/L. In trial 2, hepatocytes were incubated with azathioprine, 6-mercaptopurine, or 6-thioguanine at 1 of 3 concentrations (18.75, 37.50, or 75.00 μmol/L) for 24 hours, after which the free glutathione concentration was determined for each thiopurine-concentration combination and compared with that for hepatocytes incubated without a thiopurine (control).
  
  
  RESULTS
  Incubation of hepatocytes with each of the 3 thiopurines adversely affected cell viability in a time- and concentration-dependent manner; however, this decrease in cell viability was not accompanied by a concurrent increase in LDH or ALT activity. Likewise, free glutathione concentration for hepatocytes incubated for 24 hours with supratherapeutic thiopurine concentrations (> 18.75 μmol/L) did not differ significantly from that of control cells.
  
  
  CONCLUSIONS
  Results indicated that thiopurines adversely affected the viability of canine hepatocytes in a time- and concentration-dependent manner but had a nonsignificant effect on the LDH and ALT activities and free glutathione depletion of those hepatocytes.
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: LaDuke
authors.forename: Sarah
authors.initials: S
authors.lastname: Ehling
authors.forename: John M
authors.initials: JM
authors.lastname: Cullen
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bäumer
mesh_terms: D000818:Animals; D001379:Azathioprine / Q000008:administration & dosage / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D022781:Hepatocytes / Q000187:drug effects*; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015122:Mercaptopurine / Q000008:administration & dosage / Q000494:pharmacology; D013866:Thioguanine / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D007166:Immunosuppressive Agents; D015122:Mercaptopurine; D013866:Thioguanine; D001379:Azathioprine