Hormonal regulation of iodothyronine 5'-deiodinase in rat brown adipose tissue.
Norepinephrine, isoproterenol, insulin, and glucagon increase the type II (low Km) iodothyronine 5'-deiodinase (5'-D) in the brown adipose tissue (BAT) of intact rats. Cycloheximide or actinomycin D blocks the increase after norepinephrine, suggesting new mRNA synthesis is required for this effect. The 3- to 10-fold increase in BAT 5'-D after insulin administration was also blocked by cycloheximide. The effects of all stimulators are blunted by fasting or streptozotocin-induced diabetes. While all these hormones have the potential for stimulating BAT 5'-D, the dose-response relationships suggest that norepinephrine and insulin are the most potent. These and our earlier studies showing additional effects of thyroid and growth hormones on BAT 5'-D point to the complex regulation of this enzyme, suggesting that the triiodothyronine produced from its action has an important role in the thermogenic response of this tissue.
D002001:Adipose Tissue, Brown / Q000201:enzymology*; D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D007453:Iodide Peroxidase / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D006728:Hormones; D007328:Insulin; D003609:Dactinomycin; D005934:Glucagon; D003513:Cycloheximide; D007453:Iodide Peroxidase; D007545:Isoproterenol; D009638:Norepinephrine