This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mizuma, H. Articles by Mori, M. Search for Related Content PubMed PubMed Citation Articles by Mizuma, H. Articles by Mori, M. Related Collections Other Vascular biology Pathophysiology Risk Factors Gene expression Gene regulation

(Circulation Research. 2001;88:313.)
© 2001 American Heart Association, Inc.

Cellular Biology

Thyroid Hormone Activation in Human Vascular Smooth Muscle Cells

Expression of Type II Iodothyronine Deiodinase

Haruo Mizuma, Masami Murakami, Masatomo Mori

From the First Department of Internal Medicine, Gunma University School of Medicine, Maebashi, Japan.

Correspondence to Masami Murakami, MD, First Department of Internal Medicine, Gunma University School of Medicine, Maebashi 371-8511, Japan. E-mail mmurakam{at}showa.gunma-u.ac.jp

	Abstract

Top Abstract Introduction Materials and Methods Results Discussion References

 
Abstract—Thyroid hormone has been reported to have significant effects on the peripheral vascular system, including relaxation of vascular smooth muscle cells and antiatherosclerotic effects. To exert its biological activity, thyroxine, which is a major secretory product of thyroid gland, needs to be converted to 3,5,3'-triiodothyronine (T₃) by iodothyronine deiodinase. Type I iodothyronine deiodinase (DI) is widely distributed and maintains circulating T₃ level, whereas type II iodothyronine deiodinase (DII) is present in a limited number of tissues to provide local intracellular T₃. In the present study, we have identified iodothyronine deiodinase in cultured human coronary artery smooth muscle cells (hCASMCs) and human aortic smooth muscle cells (hASMCs). All of the characteristics of the deiodinating activity in hCASMCs and hASMCs were compatible with DII. Northern analysis demonstrated that DII mRNA was expressed in both hCASMCs and hASMCs, and DII mRNA levels as well as DII activities were rapidly increased by dibutyryl-cAMP or forskolin. These data demonstrate, for the first time, the expression of DII in human vascular smooth muscle cells, which is regulated by a cAMP-mediated mechanism. The present results suggest a previously unrecognized role of local T₃ production by DII in the pathophysiology of human vascular smooth muscle cells.

Key Words: coronary artery smooth muscle • aortic smooth muscle • thyroid hormone receptor • cAMP

	Introduction

Top Abstract Introduction Materials and Methods Results Discussion References

 
Thyroid hormone has profound effects on the peripheral vascular system. It is known as a vasodilator that acts directly on vascular smooth muscle cells (SMCs) to cause a relaxation of coronary arteries.^{1 2} Hypothyroidism is known to be a risk factor for atherosclerosis, and thyroid hormone replacement in hypothyroidism has been reported to protect from atherosclerosis.^{3 4}

To exert its biological activity, thyroxine (T₄), which is a major secretory product of the thyroid gland, needs to be converted to 3,5,3'-triiodothyronine (T₃) by iodothyronine deiodinase.^{5 6} There are two types, type I iodothyronine deiodinase (DI) and type II iodothyronine deiodinase (DII), which catalyze conversion of T₄ to T₃. DI is present in thyroid gland, liver, kidney, and many other tissues, whereas DII is present in a limited number of tissues, including central nervous system, anterior pituitary tissue, and brown fat in the rat.^{5 6} K_m of DII is 2 nmol/L for T₄, which is a hundred times lower than that of DI. DI activity is known to decrease in the hypothyroid state and is believed to have a primary role in maintaining circulating T₃ levels. DII activity, in contrast, increases in the hypothyroid state and is considered to play a critical role in providing local T₃ to regulate intracellular T₃ concentration.^{5 6} Although the source of T₃ mainly depends on circulating T₃ in most tissues, local intracellular conversion of T₄ to T₃ is an important source of T₃ in certain tissues where DII exists.^{5 6}

A cDNA encoding DII was cloned from Rana catesbeiana tissues,⁷ and its mammalian counterpart was subsequently isolated from rat brown fat.⁸ In human, DII mRNA was unexpectedly detected in thyroid gland and other tissues, suggesting previously unrecognized roles of DII in those tissues.^{9 10} Considering that not only T₃, but also T₄ has been reported to have effects on peripheral vascular function,^{11 12 13} DII may exist in vascular SMCs and may contribute to the pathophysiology of human vascular systems by providing intracellular T₃.

In the present study, we have characterized iodothyronine deiodinating activity and identified DII expression in cultured human coronary artery SMCs (hCASMCs) and human aortic SMCs (hASMCs).

	Materials and Methods

Top Abstract Introduction Materials and Methods Results Discussion References

 
Materials
[³²P]UTP, ¹²⁵I-labeled 3,3',5'-triiodothyronine (reverse T₃ [rT₃]), and [¹²⁵I]T₄ were purchased from New England Nuclear Corp. AG 50W-X2 resin and protein assay kit were from Bio-Rad Laboratories, Inc. All other chemicals were obtained from Sigma Chemical Company or Wako Pure Chemical Industries, Ltd, unless otherwise indicated.

Cell Culture
hCASMCs were obtained from Clonetics, and hASMCs were from Cascade Biologics. Both cells were demonstrated to express -smooth muscle actin isoform but not factor VIII, indicating the nature of vascular SMCs. These cells were inoculated to 6-well plastic culture plates for the measurement of deiodinase activity or to 60-mm plastic culture dishes for Northern analysis, and the cells were cultured in modified MCDB 131 medium (HuMedia-SG2, KURABO, Osaka, Japan) as previously described.¹⁴ After the cells became confluent, the medium was displaced with serum-free medium to arrest the proliferation of cells for 48 hours. The cells were then incubated in the medium containing compounds to be tested for indicated hours.

Measurement of Deiodinase Activity
Iodothyronine deiodinase activity was measured as previously described¹⁵ with minor modifications.¹⁶ Briefly, SMCs per each well (2.0x10⁶ cells per well) were washed twice with the washing buffer (100 mmol/L potassium phosphate, pH 7.0), scraped off, and transferred into 1000 µL of ice-cold buffer (100 mmol/L potassium phosphate, pH 7.0, containing 20 mmol/L DTT). After centrifugation at 3000 rpm for 15 minutes at 4°C, the supernatant was discarded. Pellets were sonicated in 100 µL of the assay buffer (in mmol/L, potassium phosphate [pH 7.0] 100, containing EDTA 1 and DTT 20) per tube and were incubated with indicated amounts of [¹²⁵I]rT₃ or [¹²⁵I]T₄, which was purified on the day of experiment, in the presence or absence of 1 mmol/L 6-propyl-2-thiouracil (PTU) or 1 mmol/L iopanoic acid. The reaction was terminated by adding 100 µL of 2% BSA and 800 µL of 10% trichloroacetic acid. The released ¹²⁵I was separated by column chromatography using AG 50W-X2 resin as previously described¹⁶ and counted. The protein concentration was determined by the Bradford method using BSA as a standard.¹⁷ The deiodinating activity was calculated either as percentage I^- released or as femtomoles of I^- released/mg protein per hour. After the characterization of deiodinase activity, the deiodinating activity was measured in duplicate by I^- release from 2 nmol/L [¹²⁵I]T₄ in the presence of 1 mmol/L PTU at 37°C for 1 hour.

Northern Analysis and Reverse Transcription–Polymerase Chain Reaction (RT-PCR)
Northern analysis and RT-PCR were performed as previously described.^{14 18 19} Total RNA was isolated from each dish, thyroid tissue, which was obtained from a patient with Graves’ disease, and cerebral cortical tissue, which was obtained from an autopsy case. In Northern analysis, mRNA levels were quantified by densitometry, and the optical density of the DII band was corrected for GAPDH. RNA samples for comparison were analyzed on the same blot, and each experiment was performed at least twice with basically identical results.

Statistics
All values are expressed as mean±SE. Statistical differences were evaluated by Student t test.

	Results

Top Abstract Introduction Materials and Methods Results Discussion References

 
Characteristics of Iodothyronine Deiodinase in hCASMCs and hASMCs
The deiodinating activity in hCASMCs was measured by the release of I^- from 2 nmol/L [¹²⁵I]T₄ or [¹²⁵I]rT₃ in the presence of 20 mmol/L DTT and 1 mmol/L PTU. T₄ deiodination was dependent on an incubation period up to 2 hours, as shown in Figure 1A and protein concentration of hCASMCs, as shown in Figure 1B. Optimal pH for the deiodination was 7.0. Incubation at 4°C or preheating the cell sonicate at 56°C for 30 minutes completely abolished the deiodination. Both the T₄ and rT₃ deiodinating activities were not influenced by 1 mmol/L PTU, but were completely inhibited by 1 mmol/L iopanoic acid. Basically identical results were obtained for hASMCs. From the double reciprocal plot, kinetic constants for T₄ were calculated to be K_m=2.3 nmol/L and V_max=333.3 fmol I^- released/mg protein per hour in hCASMCs, as shown in Figure 1C. V_max for rT₃ in hCASMCs was lower than that for T₄ (Table). In hASMCs, kinetic constants for T₄ and rT₃ were comparable with those in hCASMCs (Table). When we fractionated the hCASMC preparation,⁹ the highest deiodinating activity was observed in microsomal fraction (755.4 versus 295.3 [total cell homogenate] fmol I^- released/mg protein per hour). Taken together, these results indicate that the characteristics of the deiodinating activity in hCASMCs and hASMCs are compatible with DII.

View larger version (9K): [in this window] [in a new window]   Figure 1. Deiodinating activity in cultured hCASMCs. Deiodinating activity was measured in the sonicate of hCASMCs, as described in Materials and Methods. A, Deiodinating activity measured by various incubation periods up to 2 hours. B, Deiodinating activity measured in various protein concentrations of hCASMCs. Incubation was performed for 1 hour. C, Double reciprocal plot of T4 deiodination. Incubation was performed for 1 hour with various concentrations of T4.

View this table: [in this window] [in a new window]   Table 1. Kinetic Constants of Iodothyronine Deiodinase in hCASMCs or hASMCs

Identification of DII mRNA in Cultured hCASMCs and hASMCs
Northern analysis using human DII cRNA probe was performed to examine whether DII mRNA is expressed in human vascular SMCs. As shown in Figure 2, hybridization signals of DII mRNA 7.5 kb in size were clearly demonstrated in hCASMCs and hASMCs. The size of DII mRNA in hCASMCs and hASMCs was indistinguishable from that in human thyroid gland,⁹ although the amount of DII mRNA in hCASMCs or hASMCs was less than that in human thyroid gland. These results indicate that DII mRNA is expressed in both hCASMCs and hASMCs.

View larger version (34K): [in this window] [in a new window]   Figure 2. Northern analysis of DII mRNA in hCASMCs, hASMCs, and human thyroid tissue. Total RNA was isolated from hCASMCs, hASMCs, and thyroid tissue obtained from a patient with Graves’ disease. Northern analysis of DII mRNA was performed using 32P-labeled human DII and GAPDH cRNA probe.14 Each lane represents 10 µg of total RNA.

Regulation of DII Expression in Cultured hCASMCs and hASMCs by Thyroid Hormones
One of the important characteristics of DII is the negative regulation of its activity by thyroid hormones.^{5 6} To study the effects of thyroid hormones on deiodinating activity in human vascular SMCs, thyroid hormones were added to the culture medium for 6 hours before the harvest of cultured SMCs. As shown in Figure 3A, the deiodinating activity was decreased by thyroid hormones, and the potency of the inhibitory effect was T₄>rT₃>T₃ in hCASMCs. Although the deiodinating activity was measured by the release of I^- from [¹²⁵I]T₄, control studies demonstrated that the effects of T₄ or rT₃ on the deiodinating activity were time dependent and are thus not explained by dilution of the substrate with T₄ or rT₃ carried over into the assay of deiodinase activity. More importantly, 10^-7 mol/L rT₃ added to the assay buffer of deiodinase activity did not affect the release of I^- from [¹²⁵I]T₄. DII mRNA in hCASMCs was inhibited by thyroid hormones; the potency of the inhibitory effect was T₃>T₄>rT₃, as shown in Figure 3B. Basically identical inhibitory effects of thyroid hormones on the deiodinating activity and DII mRNA expression were observed in hASMCs. Inhibition of the deiodinating activity in hCASMCs and hASMCs by thyroid hormones further indicates the presence of authentic DII activity in cultured hCASMCs and hASMCs. These results suggest that T₃ suppresses DII activity mainly at the pretranslational level, whereas T₄ or rT₃ suppresses DII activity largely at the post-translational level in hCASMCs and hASMCs, in agreement with previous observations for DII in other tissues and cells.^{14 20 21 22}

View larger version (12K): [in this window] [in a new window]   Figure 3. Effects of thyroid hormones on DII activity and DII mRNA in hCASMCs. A, DII activity in hCASMCs incubated with serum-free medium only (control) or serum-free medium with thyroid hormones for 6 hours. DII activity was measured as described in Materials and Methods. DII activity shown represents mean±SE of 3 wells in one experiment. *P<0.05 compared with control. B, DII mRNA (DII mRNA/GAPDH mRNA ratio) in hCASMCs incubated with serum-free medium only (control) or serum-free medium with thyroid hormones for 6 hours. Optical density of the DII band was corrected for GAPDH, and results are expressed as a percentage of the value obtained for control.

Stimulation of DII Expression in Cultured hCASMCs and hASMCs by Forskolin or Dibutyryl cAMP ([Bu]₂cAMP)
Because DII activity has been known to be regulated by a cAMP-dependent mechanism,^{5 6} the effects of cAMP-elevating agents on DII expression in human vascular SMCs were studied. As shown in Figures 4A and 4B, DII activity and DII mRNA in cultured hCASMCs were clearly increased by treatment with forskolin (10^-5 mol/L) or (Bu)₂cAMP (10^-3 mol/L) for 6 hours. In the time-course study, both DII activity and DII mRNA in cultured hCASMCs were increased by forskolin within 3 hours, as shown in Figure 5. When actinomycin D (5 µg/mL) was added to the culture medium 30 minutes before the incubation with forskolin (10^-5 mol/L) for 6 hours, the stimulation of DII activity was completely abolished, indicating the requirement of mRNA synthesis for the stimulation of DII activity by a cAMP-mediated mechanism. Forskolin stimulated DII activity and DII mRNA in hASMCs in the same manner, as shown in Figure 6.

View larger version (27K): [in this window] [in a new window]   Figure 4. Effects of forskolin or (Bu)2cAMP on DII activity and DII mRNA in hCASMCs. A, DII activity in hCASMCs stimulated by forskolin (10-5 mol/L) or (Bu)2cAMP (10-3 mol/L) for 6 hours. DII activity shown represents mean±SE of 3 wells. *P<0.01 compared with control. B, Northern analysis of DII mRNA and GAPDH in hCASMCs stimulated by forskolin or (Bu)2cAMP for 6 hours. Each lane represents 10 µg of total RNA obtained from cells in individual dish.

View larger version (15K): [in this window] [in a new window]   Figure 5. Time course of forskolin stimulation of DII activity and DII mRNA in hCASMCs. •, DII activity in hCASMCs incubated with forskolin (10-5 mol/L) for various hours. DII activity shown represents mean±SE of 3 wells in one experiment. *P<0.01 compared with control. , DII mRNA (DII mRNA/GAPDH mRNA ratio) in hCASMCs incubated with forskolin for various hours. Optical density of the DII band was corrected for GAPDH, and results are expressed as a percentage of the value obtained for control (0 hours).

View larger version (16K): [in this window] [in a new window]   Figure 6. Time course of forskolin stimulation of DII activity and DII mRNA in hASMCs. •, DII activity in hASMCs incubated with forskolin (10-5 mol/L) for various hours. DII activity shown represents mean±SE of 3 wells in one experiment. *P<0.01 compared with control. , DII mRNA (DII mRNA/GAPDH mRNA ratio) in hASMCs incubated with forskolin for various hours. Optical density of the DII band was corrected for GAPDH, and results are expressed as a percentage of the value obtained for control (0 hours).

Identification of Thyroid Hormone Receptor (TR) Isoforms in Cultured hCASMCs and hASMCs by RT-PCR
To investigate whether TRs are expressed in hCASMCs and hASMCs, we have performed RT-PCR analyses of TR isoforms in those cells. In control human cerebral cortical tissue, all of the TR isoforms were clearly demonstrated by RT-PCR, as shown in Figure 7. Although all of the TR isoforms were also detected in both hCASMCs and hASMCs by RT-PCR, strong expression of mRNA for TR1 and TR2 isoforms and relatively weak expression of mRNA for TRß1 and TRß2 were observed in both hCASMCs and hASMCs, as shown in Figure 7.

View larger version (45K): [in this window] [in a new window]   Figure 7. RT-PCR of TR isoforms in hCASMCs, hASMCs, and human cerebral cortical tissue. Total RNA was isolated from hCASMCs, hASMCs, and human cerebral cortical tissue obtained at autopsy. After treatment with DNase I (Life Technologies), RT-PCR was performed on 1 µg of total RNA using AmpliTaq Gold (Roche Molecular Systems, Inc) as previously described18 with minor modifications. For PCR, the synthesized sense and antisense primers for human TR isoforms19 were the following: TR1, 5', 1659-AAGATGCCCTCAACTCACC-1677, and 3', 1870-TCTTCATTTGTCTTCTCCCC-1851; TR2, 5', 1653-ATCCCGTAAGACCTCCTTCC-1672, and 3', 1919-AAACA-GACTCATGCCCGAC-1901; TRß1, 5', 550-GAGGAGAAGAAA-TGTAAAGG-569, and 3', 717-GGAATAGGATGGATGGAG-700; and TRß2, 5', 41-GGGCTGGAGAATGCATGCGTAGACT-65 and 3', 279-ATTCACTGCCCAGGCCTGTTCCATA-255. Reaction products were analyzed by 2% agarose gel electrophoresis, and resulting bands were visualized by SYBR Green (Molecular Probes). Total RNA that was treated in an identical manner except for the substitution of water for reverse transcriptase showed no bands in RT-PCR for each TR isoform.

	Discussion

Top Abstract Introduction Materials and Methods Results Discussion References

 
The present results have clearly demonstrated that iodothyronine deiodinating activities are present in cultured hCASMCs and hASMCs. The deiodinating activities in hCASMCs and hASMCs were dependent on the protein concentrations, incubation period, pH, temperature, and substrate concentrations. These characteristics clearly indicate the enzymatic nature of the deiodinating activities. The deiodinating activities in hCASMCs and hASMCs were not inhibited by 1 mmol/L PTU and were demonstrated to have low K_m for T₄ and rT₃. Furthermore, the deiodinating activities were decreased by the addition of thyroid hormones to the culture medium. Iodothyronine deiodinating activities in hCASMCs and hASMCs, therefore, have characteristics compatible with DII. Northern analysis using human DII cRNA probe clearly demonstrated the hybridization signals with 7.5 kb in size in hCASMCs and hASMCs. The size of DII mRNA in hCASMCs and hASMCs was indistinguishable from that in human thyroid gland.⁹ The expression of DII in both hCASMCs and hASMCs suggests the ubiquitous expression of DII in human vascular SMCs. Although the expression of DII mRNA in human heart and skeletal muscle has been observed after the molecular cloning of human DII cDNA,¹⁰ the present results appear as the first demonstration of the expression of DII in human vascular SMCs.

DII activity is controlled by thyroid hormones at two levels. T₄ and rT₃ suppress DII activity mainly at the post-translational level through acceleration of the degradation rate of DII protein.²⁰ Both T₄ and rT₃ are more potent in producing this effect than T₃, suggesting that this effect does not require TRs. Recently, proteasomal degradation has been demonstrated to be involved in the post-translational regulation of DII activity by thyroid hormones.²³ In contrast, T₃ suppresses DII activity by decreasing DII mRNA without affecting its half-life, indicating that this effect is due to suppression of transcription of DII gene through TRs.²¹ Because the half-life of DII mRNA is 2 hours and that of DII enzyme is 40 minutes, the suppression of DII by thyroid hormones is very rapid whether the decrease in activity is induced by transcriptional or post-translational effects.²¹ In the present study, thyroid hormones inhibited DII mRNA expression, and the potency of the inhibitory effect was T₃>T₄>rT₃. Although the deiodinating activity was also decreased by thyroid hormones, the potency of the inhibitory effect was T₄>rT₃>T₃. These results suggest that T₃ suppresses DII activity mainly at the pretranslational level, whereasT₄ or rT₃ suppresses DII activity largely at the post-translational level in hCASMCs and hASMCs, in agreement with previous observations for DII in other tissues and cells.^{14 20 21 22} The possible transcriptional regulation of DII by T₃ is further supported by the presence of TR isoforms in hCASMCs and hASMCs demonstrated in the present study. Because DII expression in hCASMCs and hASMCs could be increased in the hypothyroid state, DII in human vascular SMCs might play a role in the protection of human vessels from local T₃ deficiency in hypothyroidism.

In the present study, both DII activities and DII mRNA levels were rapidly stimulated by forskolin or (Bu)₂cAMP in hCASMCs and hASMCs, suggesting the pretranslational regulation of DII expression by a cAMP-dependent mechanism. The rapid stimulation of DII mRNA and DII activity was also observed in human skeletal muscle cells, rat astrocytes, and pineal gland.^{14 24 25} Recently, a functional cAMP response element has been reported to be present in the human DII promoter region.²⁶ Taken together, it is suggested that DII expression in hCASMCs and hASMCs is regulated by a cAMP-dependent mechanism at the transcriptional level.

It is generally accepted that calcium-dependent phosphorylation of myosin light chains initiates the contraction of vascular smooth muscle.²⁷ Although the precise mechanisms underlying the action of endogenous vasodilator remain to be identified, it is postulated that cAMP-dependent protein kinase A inhibits calcium-dependent myosin light chain kinase.^{27 28} In the present study, it was demonstrated that intracellular accumulation of cAMP significantly stimulated DII expression in hCASMCs and hASMCs. Given that thyroid hormones have been reported to relax vascular SMCs directly,^{1 2} local production of T₃ by DII might be another vasodilative mechanism mediated by cAMP regulatory cascade.

It has been reported that low serum selenium concentration increases the risk of ischemic heart disease.²⁹ However, the mechanisms involved in the increased frequency of coronary heart disease in selenium deficiency are not known. Human DII cDNA contains in-frame TGA triplets that are not for termination codons but for the rare amino acid selenocysteine, which contains selenium.^{8 10} Because selenium is required to exert the full DII activity,²⁴ one might speculate that local T₃ production by DII in human vascular SMCs could be decreased by low serum selenium, which may be related to the increased risk of ischemic heart disease in selenium deficiency. Further studies are required to elucidate the pathophysiological roles of DII and selenium deficiency in atherosclerosis.

The physiological importance of intracellular thyroid hormone activation by DII has been clearly demonstrated in certain tissues. Adenohypophyseal T₃ production by DII plays a role in feedback regulation of thyrotropin secretion by thyroid hormones.^{5 6} In the rat brown adipose tissue, the expression of uncoupling protein is regulated by locally generated T₃, which is provided by DII.³⁰ In the present study, TRs were demonstrated in hCASMCs and hASMCs by RT-PCR, suggesting that locally produced T₃ by DII might play a role through TRs in vascular SMCs. Although the target genes induced by thyroid hormones in vascular SMCs are not known, it is of interest to study the possible role of locally produced T₃ by DII in the regulation of vascular SMC–specific gene expression, which may be associated with SMC dedifferentiation that relates to atherosclerosis and ischemic heart disease.^{31 32}

In summary, the present results demonstrate the expression of functional DII in human vascular SMCs, which may open novel perspectives on the roles of thyroid hormone metabolism in the pathophysiology of human vascular SMCs.

	Acknowledgments

 
This work was supported in part by Grant-in-Aid 09671024 (to M. Murakami) for scientific research from the Ministry of Education, Science, Sports and Culture of Japan. We are indebted to Drs Takayuki Ogiwara, Makoto Imamura, Yasuhiro Hosoi, Yuji Kamiya, Osamu Araki, Tadashi Morimura, and Tokuji Iriuchijima for their assistance and useful discussion.

	Footnotes

 
Original received May 9, 2000; resubmission received November 21, 2000; accepted December 7, 2000.

	References

Top Abstract Introduction Materials and Methods Results Discussion References

 

1. Klemperer JD, Klein I, Gomez M, Helm RE, Ojamaa K, Thomas SJ, Isom OW, Krieger K. Thyroid hormone treatment after coronary-artery bypass surgery. N Engl J Med. 1995;333:1522–1527.[Abstract/Free Full Text]
2. Ojamaa K, Klemperer JD, Klein I. Acute effects of thyroid hormone on vascular smooth muscle. Thyroid. 1996;6:505–512.[Medline] [Order article via Infotrieve]
3. Staub JJ, Althaus BU, Engler H, Ryff AS, Trabucco P, Marquardt K, Burckhardt D, Girard J, Weintraub BD. Spectrum of subclinical and overt hypothyroidism: effect on thyrotropin, prolactin, and thyroid reserve, and metabolic impact on peripheral target tissues. Am J Med. 1992;92:631–642.[Medline] [Order article via Infotrieve]
4. Perk M, O’Neill BJ. The effect of thyroid hormone therapy on angiographic coronary artery disease progression. Can J Cardiol. 1997;13:273–276.[Medline] [Order article via Infotrieve]
5. Leonard JL, Koehrle J. Intracellular pathways of iodothyronine metabolism. In: Braverman LE, Utiger RD, eds. Werner and Ingbar’s The Thyroid: A Fundamental and Clinical Text. Philadelphia: Lippincott-Raven; 1996:125–161.
6. Larsen PR. Thyroid hormone transport, cellular uptake, metabolism and molecular action. In: DeGroot LJ, Larsen PR, Hennermann G, eds. The Thyroid and its Disease. New York: Churchill Livingstone, Inc; 1996:61–111.
7. Davey JC, Becker KB, Schneider MJ, St. Germain DL, Galton VA. Cloning of a cDNA for the type II iodothyronine deiodinase. J Biol Chem. 1995;270:26786–26789.[Abstract/Free Full Text]
8. Croteau W, Davey JC, Galton VA, St. Germain DL. Cloning of the mammalian type II iodothyronine deiodinase: a selenoprotein differentially expressed and regulated in human and rat brain and other tissues. J Clin Invest. 1996;98:405–417.[Medline] [Order article via Infotrieve]
9. Salvatore D, Tu H, Harney JW, Larsen PR. Type 2 iodothyronine deiodinase is highly expressed in human thyroid. J Clin Invest. 1996;98:962–968.[Medline] [Order article via Infotrieve]
10. Salvatore D, Tibor B, Harney JW, Larsen PR. Molecular biology and biochemical characterization of the human type 2 selenodeiodinase. Endocrinology. 1996;137:3308–3315.[Abstract]
11. Ishikawa T, Chijiwa T, Hagiwara M, Mamiya S, Hidaka H. Thyroid hormones directly interact with vascular smooth muscle strips. Mol Pharmacol. 1989;35:760–765.[Abstract]
12. Zwaveling J, Pfaffendorf M, Van Zwieten PA. The direct effects of thyroid hormones on rat mesenteric resistance arteries. Fundam Clin Pharmacol. 1997;11:41–46.[Medline] [Order article via Infotrieve]
13. Park KW, Dai HB, Oiamaa K, Lowenstein E, Klein I, Sellke FW. The direct vasomotor effect of thyroid hormones on rat skeletal muscle resistance arteries. Anesth Analg. 1997;85:734–738.[Abstract]
14. Hosoi Y, Murakami M, Mizuma H, Ogiwara T, Imamura M, Mori M. Expression and regulation of type II iodothyronine deiodinase in cultured human skeletal muscle cells. J Clin Endocrinol Metab.. 1999;84:3293–3300.[Abstract/Free Full Text]
15. Leonard JL, Rosenberg IN. Iodothyronine 5'-deiodinase from rat kidney: substrate specificity and the 5'-deiodination of reverse triiodothyronine. Endocrinology.. 1980;107:1376–1383.[Medline] [Order article via Infotrieve]
16. Murakami M, Tanaka K, Greer MA, Mori M. Anterior pituitary type II thyroxine 5' deiodinase activity is not affected by lesions of the hypothalamic paraventricular nucleus which profoundly depress pituitary thyrotropin secretion. Endocrinology. 1988;123:1676–1681.[Abstract]
17. Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976;72:248–254.[Medline] [Order article via Infotrieve]
18. Murakami M, Hosoi Y, Negishi T, Kamiya Y, Miyashita K, Yamada M, Iriuchijima T, Yokoo H, Yoshida I, Tsushima Y, Mori M. Thymic hyperplasia in patients with Graves’ disease: identification of thyrotropin receptors in human thymus. J Clin Invest. 1996;98:2228–2234.[Medline] [Order article via Infotrieve]
19. Gittoes JLN, McCabe JC, Verhaeg J, Sheppard CM, Franklyn AJ. Thyroid hormone and estrogen receptor expression in normal pituitary and nonfunctional tumors of the anterior pituitary. J Clin Endocrinol Metab. 1997;82:1960–1967.[Abstract/Free Full Text]
20. Leonard JL, Silva JE, Kaplan MM, Mellen SA, Visser TJ, Larsen PR. Acute post-transcriptional regulation of cerebrocortical and pituitary iodothyronine 5'-deiodinase by thyroid hormone. Endocrinology. 1984;114:998–1004.[Abstract]
21. Kim S-W, Harney JW, Larsen PR. Studies of the hormonal regulation of type 2 5'-iodothyronine deiodinase messenger ribonucleic acid in pituitary tumor cells using semiquantitative reverse transcription-polymerase chain reaction. Endocrinology. 1998;139:4895–4905.[Abstract/Free Full Text]
22. Burmeister LA, Pachucki J, St. Germain DL. Thyroid hormones inhibit type 2 iodothyronine deiodinase in the rat cerebral cortex by both pre- and posttranslational mechanisms. Endocrinology. 1997;138:5231–5237.[Abstract/Free Full Text]
23. Steinsapir J, Harney J, Larsen PR. Type 2 iodothyronine deiodinase in rat pituitary tumor cells is inactivated in proteasomes. J Clin Invest. 1998;102:1895–1899.[Medline] [Order article via Infotrieve]
24. Pallud S, Lennon AM, Ramauge M, Gavaret JM, Croteau W, Pierre M, Courtin F, St. Germain DL. Expression of the type II iodothyronine deiodinase in cultured rat astrocytes is selenium-dependent. J Biol Chem. 1997;272:18104–18110.[Abstract/Free Full Text]
25. Kamiya Y, Murakami M, Araki O, Hosoi Y, Ogiwara T, Mizuma H, Mori M. Pretranslational regulation of rhythmic type II iodothyronine deiodinase expression by ß-adrenergic mechanism in the rat pineal gland. Endocrinology. 1999;140:1272–1278.[Abstract/Free Full Text]
26. Bartha T, Kim S-W, Salvatore D, Gereben B, Tu HM, Harney JW, Rudas P, Larsen PR. Characterization of the 5'-flanking and 5'-untranslated regions of the cyclic adenosine 3',5' monophosphate-responsive human type 2 iodothyronine deiodinase gene. Endocrinology. 2000;141:229–37.[Abstract/Free Full Text]
27. Yamagishi T, Yanagisawa T, Satoh K, Taira N. Relaxant mechanisms of cyclic AMP inducing agents in porcine coronary artery. Eur J Pharmacol. 1994;251:253–262.[Medline] [Order article via Infotrieve]
28. Walter U, Waldmann R, Nieberding M. Intracellular mechanism of action of vasodilators. Eur Heart J. 1988;9(suppl H):1–6.
29. Suadicani P, Hein HO, Gyntelberg F. Serum selenium concentration and risk of ischaemic heart disease in a prospective cohort study of 3000 males. Atherosclerosis. 1992;96:33–42.[Medline] [Order article via Infotrieve]
30. Silva JE, Rabelo R. Regulation of the uncoupling protein gene expression. Eur J Endocrinol. 1997;136:251–264.[Abstract]
31. Owens GK. Regulation of differentiation of vascular smooth muscle cells. Physiol Rev. 1995;75:487–517.[Abstract/Free Full Text]
32. Suzuki T, Nagai R, Yazaki Y. Mechanism of transcriptional regulation of gene expression in smooth muscle cells. Circ Res. 1998;82:1238–1242.[Free Full Text]

This article has been cited by other articles:

				B. Anguiano, N. Aranda, G. Delgado, and C. Aceves Epididymis Expresses the Highest 5'-Deiodinase Activity in the Male Reproductive System: Kinetic Characterization, Distribution, and Hormonal Regulation Endocrinology, August 1, 2008; 149(8): 4209 - 4217. [Abstract] [Full Text] [PDF]

				F. Galetta, F. Franzoni, P. Fallahi, L. Tocchini, L. Braccini, G. Santoro, and A. Antonelli Changes in heart rate variability and QT dispersion in patients with overt hypothyroidism Eur. J. Endocrinol., January 1, 2008; 158(1): 85 - 90. [Abstract] [Full Text] [PDF]

				K. G. Moulakakis, D. P. Sokolis, D. N. Perrea, T. Dosios, I. Dontas, M. V. Poulakou, C. A. Dimitriou, G. Sandris, and P. E. Karayannacos The Mechanical Performance and Histomorphological Structure of the Descending Aorta in Hyperthyroidism Angiology, June 1, 2007; 58(3): 343 - 352. [Abstract] [PDF]

				D. Tiosano, L. Even, Z. Shen Orr, and Z. Hochberg Recombinant Thyrotropin in the Diagnosis of Congenital Hypothyroidism J. Clin. Endocrinol. Metab., April 1, 2007; 92(4): 1434 - 1437. [Abstract] [Full Text] [PDF]

				O. Gumieniak, T. S. Perlstein, J. S. Williams, P. N. Hopkins, N. J. Brown, B. A. Raby, and G. H. Williams Ala92 Type 2 Deiodinase Allele Increases Risk for the Development of Hypertension Hypertension, March 1, 2007; 49(3): 461 - 466. [Abstract] [Full Text] [PDF]

				J.-M. Fernandez-Real, A. Lopez-Bermejo, A. Castro, R. Casamitjana, and W. Ricart Thyroid Function Is Intrinsically Linked to Insulin Sensitivity and Endothelium-Dependent Vasodilation in Healthy Euthyroid Subjects J. Clin. Endocrinol. Metab., September 1, 2006; 91(9): 3337 - 3343. [Abstract] [Full Text] [PDF]

				K. Fukuyama, T. Ichiki, I. Imayama, H. Ohtsubo, H. Ono, Y. Hashiguchi, A. Takeshita, and K. Sunagawa Thyroid Hormone Inhibits Vascular Remodeling Through Suppression of cAMP Response Element Binding Protein Activity Arterioscler. Thromb. Vasc. Biol., September 1, 2006; 26(9): 2049 - 2055. [Abstract] [Full Text] [PDF]

				O. Gumieniak, S. Hurwitz, T. S. Perlstein, U. C. Ngumezi, P. N. Hopkins, X. Jeunemaitre, and G. H. Williams Aggregation of High-Normal Thyroid-Stimulating Hormone in Hypertensive Families J. Clin. Endocrinol. Metab., November 1, 2005; 90(11): 5985 - 5990. [Abstract] [Full Text] [PDF]

				Y. Sato, R. Nakamura, M. Satoh, K. Fujishita, S. Mori, S. Ishida, T. Yamaguchi, K. Inoue, T. Nagao, and Y. Ohno Thyroid Hormone Targets Matrix Gla Protein Gene Associated With Vascular Smooth Muscle Calcification Circ. Res., September 16, 2005; 97(6): 550 - 557. [Abstract] [Full Text] [PDF]

				R. P. Peeters, A. W. van den Beld, H. Attalki, H. v. Toor, Y. B. de Rijke, G. G. J. M. Kuiper, S. W. J. Lamberts, J. A. M. J. L. Janssen, A. G. Uitterlinden, and T. J. Visser A new polymorphism in the type II deiodinase gene is associated with circulating thyroid hormone parameters Am J Physiol Endocrinol Metab, July 1, 2005; 289(1): E75 - E81. [Abstract] [Full Text] [PDF]

				T. Morimura, K. Tsunekawa, T. Kasahara, K. Seki, T. Ogiwara, M. Mori, and M. Murakami Expression of Type 2 Iodothyronine Deiodinase in Human Osteoblast Is Stimulated by Thyrotropin Endocrinology, April 1, 2005; 146(4): 2077 - 2084. [Abstract] [Full Text] [PDF]

				A. Colantuoni, P. L. Marchiafava, D. Lapi, F. S. Forini, and G. Iervasi Effects of tetraiodothyronine and triiodothyronine on hamster cheek pouch microcirculation Am J Physiol Heart Circ Physiol, April 1, 2005; 288(4): H1931 - H1936. [Abstract] [Full Text] [PDF]

				S. Yasuzawa-Amano, N. Toyoda, A. Maeda, A. Kosaki, Y. Mori, T. Iwasaka, and M. Nishikawa Expression and Regulation of Type 2 Iodothyronine Deiodinase in Rat Aorta Media Endocrinology, December 1, 2004; 145(12): 5638 - 5645. [Abstract] [Full Text] [PDF]

				O. Gumieniak, T. S. Perlstein, P. N. Hopkins, N. J. Brown, L. J. Murphey, X. Jeunemaitre, N. K. Hollenberg, and G. H. Williams Thyroid Function and Blood Pressure Homeostasis in Euthyroid Subjects J. Clin. Endocrinol. Metab., July 1, 2004; 89(7): 3455 - 3461. [Abstract] [Full Text] [PDF]

				F. Monzani, N. Caraccio, M. Kozakowa, A. Dardano, F. Vittone, A. Virdis, S. Taddei, C. Palombo, and E. Ferrannini Effect of Levothyroxine Replacement on Lipid Profile and Intima-Media Thickness in Subclinical Hypothyroidism: A Double-Blind, Placebo- Controlled Study J. Clin. Endocrinol. Metab., May 1, 2004; 89(5): 2099 - 2106. [Abstract] [Full Text] [PDF]

				A. R. Cappola and P. W. Ladenson Hypothyroidism and Atherosclerosis J. Clin. Endocrinol. Metab., June 1, 2003; 88(6): 2438 - 2444. [Full Text] [PDF]

				K. Fukuyama, T. Ichiki, K. Takeda, T. Tokunou, N. Iino, S. Masuda, M. Ishibashi, K. Egashira, H. Shimokawa, K. Hirano, et al. Downregulation of Vascular Angiotensin II Type 1 Receptor by Thyroid Hormone Hypertension, March 1, 2003; 41(3): 598 - 603. [Abstract] [Full Text] [PDF]

				K. Obuobie, J. Smith, L. M. Evans, R. John, J. S. Davies, and J. H. Lazarus Increased Central Arterial Stiffness in Hypothyroidism J. Clin. Endocrinol. Metab., October 1, 2002; 87(10): 4662 - 4666. [Abstract] [Full Text] [PDF]

				E. Fommei and G. Iervasi The Role of Thyroid Hormone in Blood Pressure Homeostasis: Evidence from Short-Term Hypothyroidism in Humans J. Clin. Endocrinol. Metab., May 1, 2002; 87(5): 1996 - 2000. [Abstract] [Full Text] [PDF]

				A. C. Bianco, D. Salvatore, B. Gereben, M. J. Berry, and P. R. Larsen Biochemistry, Cellular and Molecular Biology, and Physiological Roles of the Iodothyronine Selenodeiodinases Endocr. Rev., February 1, 2002; 23(1): 38 - 89. [Abstract] [Full Text] [PDF]

				I. Klein and K. Ojamaa Thyroid Hormone : Targeting the Vascular Smooth Muscle Cell Circ. Res., February 16, 2001; 88(3): 260 - 261. [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services