title: Methylmercury inhibition of type II 5'-deiodinase activity resulting in a decrease in growth hormone production in GH3 cells.
abstract: We have recently reported that methylmercury (MeHg) inhibits type II iodothyronine 5'-deiodinase (D2) activity in mouse neuroblastoma NB41A3 cells. In the present study, we determined the biological significance of D2 inhibition by MeHg. GH3 rat pituitary tumor cells were treated with MeHg and D2 activity and production of a thyroid hormone-responsive gene product, growth hormone (GH) were analyzed. MeHg inhibited D2 activity and decreased thyroxine (T4)-induced, but not 3,3',5-triiodothyronine (T3)-induced GH secretion in GH3 cells. Our results suggest that MeHg inhibition of D2 activity might be involved in the inhibition of GH production in GH3 cells. Thus, D2 inhibition could be a novel mechanism involved in MeHg toxicity.
authors.affiliation: Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: kokimori@mail.tains.tohoku.ac.jp.
authors.forename: Kouki
authors.initials: K
authors.lastname: Mori
authors.affiliation: Department of Medical Technology, Tohoku University School of Health Sciences, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan. Electronic address: kayosi2i@mail.tains.tohoku.ac.jp.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: akkosuzuka@yahoo.co.jp.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nakagawa
authors.affiliation: Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: zxc06115@nifty.ne.jp.
authors.forename: Saeko
authors.initials: S
authors.lastname: Hoshikawa
authors.affiliation: Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: ho2117@mail.tains.tohoku.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ozaki
authors.affiliation: Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: db554@mail.tains.tohoku.ac.jp.
authors.forename: Sadayoshi
authors.initials: S
authors.lastname: Ito
authors.affiliation: Department of Human Ecology, Graduate School of Medical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Electronic address: chiho@humeco.m.u-tokyo.ac.jp.
authors.forename: Chiho
authors.initials: C
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D003470:Culture Media; D004791:Enzyme Inhibitors / Q000633:toxicity*; D013006:Growth Hormone / Q000096:biosynthesis*; D007453:Iodide Peroxidase / Q000037:antagonists & inhibitors*; D008767:Methylmercury Compounds / Q000633:toxicity*; D051381:Rats; D013974:Thyroxine / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology; D000097564:Iodothyronine Deiodinase Type II
chemical_list: D003470:Culture Media; D004791:Enzyme Inhibitors; D013006:Growth Hormone; D007453:Iodide Peroxidase; D008767:Methylmercury Compounds; D013974:Thyroxine; D014284:Triiodothyronine; D000097564:Iodothyronine Deiodinase Type II; C004925:methylmercuric chloride