Partial reversal of alpha 2u globulin gene expression by thyroxine in the liver of diabetic rats.
Synthesis of alpha 2u globulin and its mRNA has been used as an index to monitor the effect of thyroxine on specific gene expression in the liver of hypoinsulinemic male rats. Administration of a physiological dose of thyroxine can partially reverse (to approximately 30% of the normal control) the marked reduction (more than 90%) in the hepatic levels of alpha 2u globulin and its mRNA during streptozotocin-induced diabetes. Estimation of newly synthesized alpha 2u globulin RNA transcripts from the native chromatin of isolated liver nuclei by "nuclear runoff experiments" showed that thyroxine can elevate the rate of transcription of alpha 2u globulin gene in the diabetic rat. Hypoinsulinemic diabetes is also found to be associated with an approximately 35% reduction in the thyroid hormone receptor level as compared to the normal control. The stimulatory effect of thyroxine on the synthesis of alpha 2u globulin and its mRNA was also evident in spontaneous diabetic Wistar "BB" rats. From these studies it can be concluded that severe hypoinsulinemia can cause a decrease in thyroid hormone action at the level of specific gene expression.
D000510:Alpha-Globulins / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005796:Genes / Q000187:drug effects*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains; D011988:Receptors, Thyroid Hormone / Q000378:metabolism; D013974:Thyroxine / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*; D014284:Triiodothyronine / Q000378:metabolism
D000510:Alpha-Globulins; D012333:RNA, Messenger; D011988:Receptors, Thyroid Hormone; C013803:alpha 2u globulin; D014284:Triiodothyronine; D004247:DNA; D013974:Thyroxine