Archives of Toxicology

, Volume 87, Issue 2, pp 337–345

Pharmacokinetics explain in vivo/in vitro discrepancies of carcinogen-induced gene expression alterations in rat liver and cultivated hepatocytes

  • Markus Schug
  • Regina Stöber
  • Tanja Heise
  • Hans Mielke
  • Ursula Gundert-Remy
  • Patricio Godoy
  • Raymond Reif
  • Meinolf Blaszkewicz
  • Heidrun Ellinger-Ziegelbauer
  • Hans-Jürgen Ahr
  • Silvia Selinski
  • Georgia Günther
  • Rosemarie Marchan
  • Meinolf Blaszkewicz
  • Agapios Sachinidis
  • Andreas Nüssler
  • Axel Oberemm
  • Jan G. Hengstler
In vitro systems

DOI: 10.1007/s00204-012-0999-8

Cite this article as:
Schug, M., Stöber, R., Heise, T. et al. Arch Toxicol (2013) 87: 337. doi:10.1007/s00204-012-0999-8

Abstract

Cultivated hepatocytes represent a well-established in vitro system. However, the applicability of hepatocytes in toxicogenomics is still controversially discussed. Recently, an in vivo/in vitro discrepancy has been described, whereby the non-genotoxic rat liver carcinogen methapyrilene alters the expression of the metabolizing genes SULT1A1 and ABAT, as well as the DNA damage response gene GADD34 in vitro, but not in vivo. If the collagen sandwich cultures of hepatocytes really produce false-positive data, this would compromise its application in toxicogenomics. To revisit the putative in vivo/in vitro discrepancy, we first analyzed and modeled methapyrilene concentrations in the portal vein of rats. The relatively short half-life of 2.8 h implies a rapid decrease in orally administered methapyrilene in vivo below concentrations that can cause gene expression alterations. This corresponded to the time-dependent alteration levels of GADD34, ABAT and SULT1A1 RNA in the liver: RNA levels are altered 1, 6 and 12 h after methapyrilene administration, but return to control levels after 24 and 72 h. In contrast, methapyrilene concentrations in the culture medium supernatant of primary rat hepatocyte cultures decreased slowly. This explains why GADD34, ABAT and SULT1A1 were still deregulated after 24 h exposure in vitro, but not in vivo. It should also be considered that the earliest analyzed time point in the previous in vivo studies was 24 h after methapyrilene administration. In conclusion, previously observed in vitro/in vivo discrepancy can be explained by different pharmacokinetics present in vitro and in vivo. When the in vivo half-life is short, levels of some initially altered genes may have returned to control levels already 24 h after administration.

Keywords

Hepatocyte in vitro system Alternative methods In vitro/in vivo comparison Genotoxic and non-genotoxic carcinogens In vitro pharmacokinetics 

Abbreviations

SULT1A1

Sulfotransferase

ABAT

4-aminobutyrate aminotransferase

GADD34

Growth arrest and DNA damage inducible gene 34

ABCB1

Multi drug resistance protein 1NQO1: NADPH-quinone oxidoreductase

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Markus Schug
    • 1
  • Regina Stöber
    • 1
  • Tanja Heise
    • 2
  • Hans Mielke
    • 2
  • Ursula Gundert-Remy
    • 2
  • Patricio Godoy
    • 1
  • Raymond Reif
    • 1
  • Meinolf Blaszkewicz
    • 1
  • Heidrun Ellinger-Ziegelbauer
    • 3
  • Hans-Jürgen Ahr
    • 3
  • Silvia Selinski
    • 1
  • Georgia Günther
    • 1
  • Rosemarie Marchan
    • 1
  • Meinolf Blaszkewicz
    • 1
  • Agapios Sachinidis
    • 4
  • Andreas Nüssler
    • 5
  • Axel Oberemm
    • 3
  • Jan G. Hengstler
    • 1
  1. 1.Leibniz Research Centre for Working Environment and Human Factors (IfADo) at Dortmund TUDortmundGermany
  2. 2.Federal Institute for Risk AssessmentBerlinGermany
  3. 3.Department of Molecular and Genetic ToxicologyBayer AGWuppertalGermany
  4. 4.Center of Physiology and Pathophysiology, Institute of NeurophysiologyUniversity of CologneCologneGermany
  5. 5.BG Unfallklinik TübingenEberhard-Karls Universität TübingenTuebingenGermany

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