Effects of hyperthyroidism on expression of a phosphoenolpyruvate carboxykinase/bovine growth hormone gene in transgenic mice.
Thyroid hormone (T3) responsiveness of the PEPCK promoter in vivo was examined in both PEPCK/bGH(460) and PEPCK/bGH(335) mouse lines. Transgenic and non-transgenic littermates were treated with methimazole or PTU for 6 or 4 weeks, respectively, then treated +/- T3 for 10 days. In PEPCK/bGH(460) and PEPCK/bGH(355) transgenic mice, the bGH mRNA was decreased by 65% and 46%, respectively, in hyperthyroid mice when compared to euthyroid controls. Endogenous PEPCK mRNA was decreased by 33% in hyperthyroid non-transgenic mice. The conclusion of this study is that chronic hyperthyroidism in mice inhibits PEPCK-directed expression of the transgene when either the -460/+73 or the -355/+73 promoter/regulatory elements are used.
Xu
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Department of Nutritional Sciences, University of Connecticut, Storrs 06269, USA.
McGrane
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D000818:Animals; D013956:Antithyroid Agents / Q000494:pharmacology; D002417:Cattle; D015971:Gene Expression Regulation, Enzymologic; D013006:Growth Hormone / Q000235:genetics; D006980:Hyperthyroidism / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008713:Methimazole / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D014284:Triiodothyronine / Q000494:pharmacology
D013956:Antithyroid Agents; D012333:RNA, Messenger; D014284:Triiodothyronine; D008713:Methimazole; D013006:Growth Hormone; D010729:Phosphoenolpyruvate Carboxykinase (GTP)