3,3′,5′-Triiodothyronine inhibits ontogenetic development of iodothyronine-5′-deiodinase in the liver of the neonatal mouse

Han, Doo Chol; Sato, Kanji; Fujii, Yuko; Ozawa, Minoru; Imamura, Hironori; Tsushima, Takahiro; Shizume, Kazuo

doi:10.1530/acta.0.1190181

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…should be regarded with caution. The contamination of rT3 preparations from Calbiochem-Behring Corp. is rather unlikely since HAN et al (1988) were not able to detect any T3 and the level of T4 did not exceed 0.5 %.…”

Section: Discussionmentioning

confidence: 95%

“…Contrary to T3, rT3 decreases basal metabolic rate in mammals and fowl (LYNCH et al, 1985;VYBIRAL et al, 1985;ABDEL-FATTAH et al, 1990) and attenuates the hypermetabolic properties of T3 (ABDEL-FATTAH et al, 1990). Reverse TO also reduces the synthesis of T3 from T4 by reducing the activity of 5'-deiodinase type I and I1 (KAISER et al, 1986;HAN et al, 1988). CHOPRA (1977) has suggested that rT3 interacts with the binding sites of T3 in target cells.…”

Section: Introductionmentioning

confidence: 99%

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Responses of Heat Stressed Chickens to Exogenous Reverse Triiodothyronine (rT₃)

Bobek

Sechman

Wieczorek

et al. 1996

Journal of Veterinary Medicine Series A

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Heat stress is accompanied by a decrease in basal metabolic rate and plasma thyroid hormones..Unlike 3,5,3'-triiodothyronhe (T3) and thyroxine (T.J, 3,3',5'-uiiodothyronhe (rT3) displays hypometabolic properties and antagonizes the hypermetabolic effect of T3. This study analyses the role of rT3 in heat (38-39 "C) stressed immature chickens. Two experiments which differed in frequency of rT3 injections (one or two times a day), duration of heat stress (72 or 48 h) and blood samphg were performed. The dose was 14 pg rT3/100 g b.wt./injection (s.c.). It has been shown that rT3 treatment aggravates heat stress symptoms (enhances circulating corticosterone, catecholamines and free fatty acids) and increases mortality. The critical suMval time of the rT3 treated and heated birds was at first 24 h of stress. No more chickens died during the next days of the experiment despite the continuation of rT3 injection, suggesting that rT3 might disturb the adaptation to heat. Reverse T3 in heat stressed chickens led to the hghest reduction in food consumption (69.9 Yo) and body weight gain (14.0 Yo compared to initial weight). The opposite effect in water consumption (216.9 Yo) was observed. In a neutral environment, rT3 significantly suppressed body temperature 6 h after injection (40.4; control: 41.1 "C), confirming its hypometabolic properties. However, at the same time rT3 significantly enhanced body temperature in heat stress (43.03 versus heated control 42.56 "C). In addition, in rT3 treated birds decreased plasma triglycerides (TG, 24.3 Yo) and increased plasma free fatty acids (FFA, neutral temperature: 26.4 Yo; heat stress: 57 Yo) were demonstrated. A correlation between corticosterone and FFA (r = 0.52) shows that some of the FFA may originate from lipolysis since hormones of the pituitary-adrenocortical axis accelerate lipolysis. The remaining part of the increased FFA appears to be due to suppressed utilization of FFA as a consequence of hypometabolic properties of rT3. Low and negative reladon between TG and FFA (r = -0.26; P < 0.05) may support such an assumption. The two times higher peak of corticosterone in the rT3 and the overheated group, as compared to the heated control, occurred at 6 h of heat stress and indicates that rT3 increases the unfavourable effect of high temperature. This was also confirmed by elevated plasma adrenaline and noradrenaline in rT3-injected and heated chickens (55.5 and 120Y0, respectively). However, a single and two times higher peak of adrenaline at 24 h of heat stress was observed in saline treated birds, but not in rT3 supplemented animals, suggesting that this difference might explain one of the factors responsible for high mortality. In conclusion, the results obtained demonstrate that physiological doses of rT3, a hypometabolic hormone, enhance the unfavourable effect of heat stress in chickens. US. Copyright ~a m c cCenter Code Statement: 0931-1 84X/96/4309-0521$11.50/0

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Responses of Heat Stressed Chickens to Exogenous Reverse Triiodothyronine (rT₃)

Bobek

Sechman

Wieczorek

et al. 1996

Journal of Veterinary Medicine Series A

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Statistical Evidence that Endogenous Reverse Triiodothyronine (rT₃) May Affect Oxygen Consumption in Food Deprived Chickens

Bobek

Sechman

Abdel-Fattah

et al. 1993

Journal of Veterinary Medicine Series A

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Summary Exogenous rT3 decreases O2 consumption in mammals and birds. Until now a correlation coefficient and a regression equation have not been presented. Statistical evaluation seems to be requisite for verifying the answer to the question of whether endogenous rT3 may be able to reduce O2 consumption in birds where the normal level of plasma rT3 is 10 times less than the corresponding level of T3. Food deprived chickens (for 48 h) were used in this study because fasting enhances plasma rT3. The results revealed a reciprocal relation of T3 and rT3 in the circulation. Reverse T3 began to increase when T3 decreased to a plateau at 53.9% of initial level. As expected a reciprocal relationship was obtained (r = −0.749; n = 36) between plasma rT3 and O2 consumption. The regression line was calculated according to the equation: Ŷ = −0.388X + 0.856. This relation differs from the linear relationship between T3 and O2 consumption (r = 0.796; Ŷ = 0.107X + 0.449). The regression line lies in the range of 0.122–0.778 nmol rT3/l, which is found in some physiological conditions in birds where elevated plasma rT3 occurs. This suggests that endogenous rT3 may participate in modifying O2 consumption in birds. Using the rT3: T3 ratio the correlation coefficient was somewhat higher (r = −0.831; Ŷ = −0.673X + 0.831) suggesting common involvement of both triiodothyronines in the reduction of O2 consumption during food deprivation. The drop in O2 consumption after 48 h of food deprivation was 28.4%; decreased T3 and increased rT3 may participate in 15.4% and 13.0% of this fall, respectively. The hypometabolic effectiveness of rT3 seems to be greater than the hypermetabolic effectiveness of T3, since a smaller increase of plasma rT3 was needed to reduce O2 consumption compared to the amount of T3 necessary to enhance it.

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Ontogeny of Iodothyronine Deiodinases in Human Liver1

Richard

Hume

Kaptein

et al. 1998

The Journal of Clinical Endocrinology &Amp; Metabolism

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The role of the deiodinases D1, D2, and D3 in the tissue-specific and time-dependent regulation of thyroid hormone bioactivity during fetal development has been investigated in animals but little is known about the ontogeny of these enzymes in humans. We analyzed D1, D2, and D3 activities in liver microsomes from 10 fetuses of 15-20 weeks gestation and from 8 apparently healthy adult tissue transplant donors, and in liver homogenates from 2 fetuses (20 weeks gestation), 5 preterm infants (27-32 weeks gestation), and 13 term infants who survived up to 39 weeks postnatally. D1 activity was determined using 1 M [3Ј, 5Ј-125 I]rT 3 as substrate and 10 mM dithiothreitol (DTT) as cofactor, D2 activity using 1 nM [3Ј, 5Ј-125 I]T 4 and 25 mM DTT in the presence of 1 mM 6-propyl-2-thiouracil (to block D1 activity) and 1 M T 3 (to block D3 activity), and D3 activity using 10 nM [3, I]T 3 and 50 mM DTT, by quantitation of the release of 125 I Ϫ . The assays were validated by high performance liquid chromatography of the products, and kinetic analysis [Michaelis-Menten constant (K m ) of rT 3 for D1: 0.5 M; K m of T 3 for D3: 2 nM]. In liver homogenates, D1 activity was not correlated with age, whereas D3 activity showed a strong negative correlation with age (r Ϫ0.84), with high D3 activities in preterm infants and (except in 1 infant of 35 weeks) absent D3 activity in full-term infants. In microsomes, D1 activities amounted to 4.3-60 pmol/min/mg protein in fetal livers and to 170 -313 pmol/min/mg protein in adult livers, whereas microsomal D3 activities were 0.15-1.45 pmol/min/mg protein in fetuses and Ͻ0.1 pmol/min/mg protein in all but one adult. In the latter sample, D3 activity amounted to 0.36 pmol/min/mg protein. D2 activity was negligible in both fetal and adult livers. These findings indicate high D1 and D3 activities in fetal human liver, and high D1 and mostly absent D3 activities in adult human liver. Therefore, the low serum T 3 levels in the human fetus appear to be caused by high hepatic (and placental) D3 activity rather than caused by low hepatic D1 activity. The occasional expression of D3 in adult human liver is intriguing and deserves further investigation. (J Clin Endocrinol Metab 83: 2868 -2874, 1998 T HE bioactivity of thyroid hormone is regulated importantly by enzymatic deiodination in peripheral tissues (1-4). The prohormone T 4 is converted by outer ring deiodination (ORD) to the active hormone T 3 . Both T 4 and T 3 are inactivated by inner ring deiodination (IRD) to rT 3 and 3,3Ј-diiodothyronine (3,3Ј-T 2 ), respectively. The latter metabolite is also produced by ORD of rT 3 . The three iodothyronine deiodinases involved in these processes have been characterized as homologous transmembrane selenoproteins that require thiols as cofactor (1-4). The type I deiodinase (D1) has both ORD and IRD activity. It is located in liver, kidney, and thyroid and is important for plasma T 3 production. rT 3 is the preferred substrate for D1, although the deiodination of other iodothyronines is greatly a...

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3,3′,5′-Triiodothyronine inhibits ontogenetic development of iodothyronine-5′-deiodinase in the liver of the neonatal mouse

Cited by 3 publications

References 15 publications

Responses of Heat Stressed Chickens to Exogenous Reverse Triiodothyronine (rT₃)

Responses of Heat Stressed Chickens to Exogenous Reverse Triiodothyronine (rT₃)

Statistical Evidence that Endogenous Reverse Triiodothyronine (rT₃) May Affect Oxygen Consumption in Food Deprived Chickens

Ontogeny of Iodothyronine Deiodinases in Human Liver1

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3,3′,5′-Triiodothyronine inhibits ontogenetic development of iodothyronine-5′-deiodinase in the liver of the neonatal mouse

Cited by 3 publications

References 15 publications

Responses of Heat Stressed Chickens to Exogenous Reverse Triiodothyronine (rT3)

Responses of Heat Stressed Chickens to Exogenous Reverse Triiodothyronine (rT3)

Statistical Evidence that Endogenous Reverse Triiodothyronine (rT3) May Affect Oxygen Consumption in Food Deprived Chickens

Ontogeny of Iodothyronine Deiodinases in Human Liver1

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Responses of Heat Stressed Chickens to Exogenous Reverse Triiodothyronine (rT₃)

Responses of Heat Stressed Chickens to Exogenous Reverse Triiodothyronine (rT₃)

Statistical Evidence that Endogenous Reverse Triiodothyronine (rT₃) May Affect Oxygen Consumption in Food Deprived Chickens