Methylmercury inhibition of type II 5'-deiodinase activity resulting in a decrease in growth hormone production in GH3 cells.
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.
Mori
Kouki
K
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.
Yoshida
Katsumi
K
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.
Nakagawa
Yoshinori
Y
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.
Hoshikawa
Saeko
S
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.
Ozaki
Hiroshi
H
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.
Ito
Sadayoshi
S
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.
Watanabe
Chiho
C
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.
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
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