Catecholamine stimulation of iodothyronine 5'-deiodinase activity in rat dispersed brown adipocytes.
We describe an in vitro system for evaluating the direct effects of catecholamines on the activity of the type II iodothyronine 5'-deiodinase in dispersed rat brown adipocytes. Incubation with norepinephrine or phenylephrine for 3-4 h causes up to a 5-fold increase in deiodinase activity in these cells. As found in vivo studies, the norepinephrine stimulation is blocked by coincubation with the alpha 1-adrenergic antagonist prazosin. The beta-adrenergic antagonist alprenolol either has no effect or increases stimulation by norepinephrine. These results suggest that beta-adrenergic agonists inhibit the activation or synthesis of the deiodinase in these cells.
D002001:Adipose Tissue, Brown / Q000201:enzymology*; D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D066298:In Vitro Techniques; D007453:Iodide Peroxidase / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D010656:Phenylephrine; D003513:Cycloheximide; D007453:Iodide Peroxidase; D004229:Dithiothreitol; D009638:Norepinephrine