title: Type 1 iodothyronine deiodinase in the house musk shrew (Suncus murinus, Insectivora: Soricidae): cloning and characterization of complementary DNA, unique tissue distribution and regulation by T(3).
abstract: The house musk shrew Suncus murinus (Insectivora: Soricidae) has been reported as having low thyroxine to 3,3'5-triiodothyronine (T(3)) converting activity in liver and kidney homogenates and was assumed to be type 1 iodothyronine deiodinase (D1)-deficient. To study whether this is due to structural abnormality of shrew D1, we cloned the cDNA and characterized the enzyme. The deduced amino acid sequence of shrew D1 was found to be highly homologous to other known D1s and the enzyme itself to have similar catalytic activity. However, unlike in other species, the D1 activity was detected only in liver. Moreover, the D1 activity in liver of the shrew was less than half of that in rat liver and its expression was not up-regulated by T(3). In contrast, a very high activity of D2 was demonstrated in brain and brown adipose tissue. The present study also revealed that the serum level of T(3) in the shrew was in the same range as these in other mammals. These results suggest that D2 contributes to the production and maintenance of T(3) levels in the house musk shrew.
authors.affiliation: Department of Teratology and Genetics, Division of Molecular and Cellular Adaptation, Research Institute of Environmental Medicine, Nagoya University, Japan.
authors.forename: Margarita
authors.initials: M
authors.lastname: Rogatcheva
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Sen
authors.initials: S
authors.lastname: Oda
authors.forename: Hisao
authors.initials: H
authors.lastname: Seo
authors.forename: Kevin
authors.initials: K
authors.lastname: Cua
authors.forename: Samuel
authors.initials: S
authors.lastname: Refetoff
authors.forename: Masami
authors.initials: M
authors.lastname: Murakami
authors.forename: Masatomo
authors.initials: M
authors.lastname: Mori
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Murata
mesh_terms: D002001:Adipose Tissue, Brown / Q000201:enzymology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000737:chemistry; D002540:Cerebral Cortex / Q000201:enzymology; D003001:Cloning, Molecular; D018076:DNA, Complementary; D019143:Evolution, Molecular; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D007453:Iodide Peroxidase / Q000032:analysis / Q000737:chemistry / Q000235:genetics*; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000201:enzymology; D012333:RNA, Messenger / Q000032:analysis; D011988:Receptors, Thyroid Hormone / Q000032:analysis; D012788:Shrews / Q000235:genetics* / Q000378:metabolism; D013961:Thyroid Gland / Q000201:enzymology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014018:Tissue Distribution; D014284:Triiodothyronine / Q000097:blood / Q000494:pharmacology*; D014285:Triiodothyronine, Reverse / Q000097:blood
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D011988:Receptors, Thyroid Hormone; D014284:Triiodothyronine; D014285:Triiodothyronine, Reverse; D013972:Thyrotropin; D007453:Iodide Peroxidase; D013974:Thyroxine