Defective cold-induced stimulation of thyroxine 5'-deiodinase in brown adipose tissue of the genetically obese (ob/ob) mouse.
Exposure of a normal lean mouse to cold (14 degrees C) for 12 h increases the activity of thyroxine 5'-deiodinase in brown adipose tissue 26-fold. In contrast, exposure of the genetically obese, ob/ob, mouse to cold results in little more than a doubling of thyroxine 5'-deiodinase activity. The physiological significance of endogenous 3,5,3'-triiodothyronine production in brown adipose tissue is not understood. However, it seems likely that defective cold-induced stimulation of the 5'-deiodinase in brown adipose tissue of the ob/ob mouse might cause a relatively hypothyroid state of the tissue. Thyroid hormone is known to be required for a normal thermogenic response of brown adipose tissue to noradrenaline. It is suggested that the defect in the response of the 5'-deiodinase in the ob/ob mouse could contribute to the defective thermogenic response of brown adipose tissue to cold-exposure and to noradrenaline.
D002001:Adipose Tissue, Brown / Q000201:enzymology*; D000818:Animals; D001833:Body Temperature Regulation; D003080:Cold Temperature; D004789:Enzyme Activation; D005260:Female; D007453:Iodide Peroxidase / Q000378:metabolism*; D051379:Mice; D008820:Mice, Obese / Q000378:metabolism*; D009638:Norepinephrine / Q000502:physiology; D010544:Peroxidases / Q000378:metabolism*; D013974:Thyroxine / Q000378:metabolism*; D014284:Triiodothyronine / Q000096:biosynthesis*
D014284:Triiodothyronine; D010544:Peroxidases; D007453:Iodide Peroxidase; D013974:Thyroxine; D009638:Norepinephrine