MORIMOTO Satoshi    Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine    Position   Associate Professor
Article types	Original article
Language	English
Peer review	Peer reviewed
Title	Type 2 iodothyronine deiodinase is expressed in human preadipocytes.
Journal	Formal name：Thyroid : official journal of the American Thyroid Association Abbreviation：Thyroid ISSN code：15579077/10507256
Domestic / Foregin	Foregin
Volume, Issue, Page	21(3),pp.305-10
Author and coauthor	Nomura Emiko, Toyoda Nagaoki, Harada Azusa, Nishimura Kumiko, Ukita Chizuko, Morimoto Satoshi, Kosaki Atsushi, Iwasaka Toshiji, Nishikawa Mitsushige
Publication date	2011/03
Summary	BACKGROUND:Type 2 iodothyronine deiodinase (D2) is an enzyme that catalyzes the production of triiodothyronine (T3) from thyroxine (T4) and plays a critical role in providing the local intracellular T3. Although D2 is highly expressed in brown adipose tissue, it was thought that D2 is hardly expressed in white adipose tissue. In the present study, we examined whether D2 is expressed in human preadipocytes, using human mesenteric and subcutaneous preadipocytes (HMPA and HSCPA, respectively).METHODS:HMPA and HSCPA were purchased and cultured in the preadipocyte medium containing 10% fetal bovine serum. We measured D2 activity and mRNA level in HMPA and HSCPA incubated with or without dibutyryl cyclic adenosine monophosphate [(Bu)₂cAMP].RESULTS:D2 activity and mRNA were detectable in human HMPA and HSCPA. The apparent Michaelis-Menten constant (K(m)) value for T4 in HMPA was 2.1 ± 0.2 nM, and the maximum velocity (V(max)) value was 333.3 ± 28.0 femtomols of I⁻ released/mg protein/hour, respectively. On the other hand, the apparent K(m) value for T4 in HSCPA was 2.0 ± 0.2 nM and the V(max) value was 91.2 ± 8.7 femtomols of I⁻ released/mg protein/hour, respectively. D2 activities in HMPA and HSCPA incubated with 1 mM (Bu)₂cAMP for 24 hours were 7-fold (HMPA) and 3-fold (HSCPA) higher than those without (Bu)₂cAMP, respectively. D2 mRNA levels in HMPA and HSCPA incubated with 1 mM (Bu)₂cAMP for 3 hours were 10-fold (HMPA) and 5-fold (HSCPA) higher than those without (Bu)₂cAMP, respectively.CONCLUSIONS:In the present study, we have clearly demonstrated that D2 activity and mRNA are present in the human preadipocytes from both mesenteric and subcutaneous adipose tissue. Our experiments are the first ones that identify human preadipocytes as one of the sources of T3 production.
DOI	10.1089/thy.2010.0068
PMID	21323585