Effect of reserpine pretreatment on brown fat iodothyronine 5'-deiodinase of mouse.
The effect of pretreatment with reserpine (1 mg kg-1 i.p. daily for 7 days) on the regulation of iodothyronine 5'-deiodinase (5'D) in mouse brown adipose tissue (BAT) has been examined. 5'D activity of BAT homogenate was assessed by the in-vitro formation of 3,5,3'-triiodothyronine from thyroxine and 3,3'-diiodothyronine from 3,3',5'-triiodothyronine in the presence of 20 mM dithiothreitol. Reserpine treatment decreased the stimulation of BAT 5'D induced by acute cold exposure (4 degrees C, 2 h) without a significant decrease in the basal 5'D activity, whereas stimulation of BAT 5'D elicited by noradrenaline (0.4 and 0.8 mg kg-1 s.c. 2 h previously) was not augmented after reserpine treatment. Although both noradrenaline and acute cold exposure increase BAT 5'D through alpha 1-adrenoceptors, our results show that chronic reserpine treatment prevents the effect of cold, but does not induce alpha 1-adrenoceptor supersensitivity in BAT.
Muraki
T
T
Department of Pharmacology, Tokyo Women's Medical College, Japan.
Tsukahara
F
F
Oike
N
N
Nomoto
T
T
D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000201:enzymology*; D000818:Animals; D003080:Cold Temperature; D005260:Female; D007453:Iodide Peroxidase / Q000378:metabolism*; D007457:Iodine Radioisotopes; D051379:Mice; D008820:Mice, Obese; D009638:Norepinephrine / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D012110:Reserpine / Q000494:pharmacology*; D013974:Thyroxine / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism
D007457:Iodine Radioisotopes; D011942:Receptors, Adrenergic, alpha; D014284:Triiodothyronine; D012110:Reserpine; D007453:Iodide Peroxidase; D013974:Thyroxine; D009638:Norepinephrine