Thyroxine 5'-deiodinase and thyroid hormone metabolism in intermediate and neural lobes of rat posterior pituitary.
We have found thyroxine 5'-deiodinase in rat posterior pituitary. The isozyme pattern was different in intermediate and neural lobes. The former contained only type I enzyme. In the neural lobe, in euthyroidism only type I was found while in hypothyroidism type II was a prominent form. Since type II 5'-deiodinase has a high affinity for thyroxine and is a more tissue-specific isozyme than type I, our results suggest there may be a previously unrecognized role of thyroid hormone in posterior pituitary physiology.
Department of Medicine, Oregon Health Sciences University, Portland.
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K
Tanaka
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Murakami
M A
MA
Greer
D000818:Animals; D005260:Female; D007453:Iodide Peroxidase / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000201:enzymology / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013974:Thyroxine / Q000378:metabolism*; D014284:Triiodothyronine / Q000378:metabolism*
D014284:Triiodothyronine; D007453:Iodide Peroxidase; D013974:Thyroxine