Dioxin-responsive Genes: Examination of Dose-Response Relationships Using Quantitative Reverse Transcriptase-Polymerase Chain Reaction

摘要: The purpose of the present experiments was to examine dose-response relationships for induction hepatic mRNA following a single administration 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) rats. cytochrome P450-1A1 (CYP1A1) is compared other "dioxin-responsive" genes including UDP-glucuronosyltransferase I, plasminogen activator inhibitor 2, and transforming growth factor alpha using sensitive reverse transcriptase-polymerase chain reaction-based method. Sample-to-sample variability in amplification concern polymerase reaction quantitate biological responses. However, study recombinant RNA templates were synthesized use as internal standards both transcription steps. CYP1A1 extremely TCDD treatment with increases observed at doses low 1 ng/kg body weight. correlated highly (R2 > 0.90) an increase ethoxyresorufin-o-deethylase activity, CYP1A1-associated enzyme activity. levels detected lower than reflecting greater sensitivity transcription-polymerase approach detect transcriptional activation gene. I increased over control (5-fold) but required 1000-times higher (1 microgram/kg) result significant did CYP1A1. Plasminogen 2 mRNA, previously shown be induced by human keratinocytes, not rat liver. Hence, these studies reaffirm that acts through classical receptor mechanisms gene-to-gene differences responsiveness. method developed measure dioxin-responsive liver will allow measuring multigene tissue responses xenobiotics high sensitivity, reproducibility, adaptability should our understanding various relationships.