Conversion of Thyroxine into Tri-iodothyronine in Zinc Deficient Rat Liver

Fujimoto, Shigehiro; Indo, Yasuhiro; Higashi, Akimasa; Matsuda, Ichiro; Kashiwabara, Norio; Nakashima, Ichiro

doi:10.1097/00005176-198609000-00023

Cited by 22 publications

(14 citation statements)

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“…Serum Zn con centrations in the present study are in agree ment with the observations of other workers [9,11,12] who have also reported reduction in serum Zn concentrations in ZnD guineapigs. Growth retardation due to Zn deficiency in guinea-pigs as observed in the present study has also been reported in other species of animals [14], This might be due to impair ment of DNA synthesis since during Zn defi ciency the enzymes (thymidine kinase and DNA polymerase) and a hormone, somato medin C, required for DNA synthesis have been reported to be decreased [14,15], Sec ondly, hypothyroidism might have also con tributed to growth retardation [14], Lower values of serum T3 and T4 observed in ZnD guinea-pigs of the present study have also been found to be associated with Zn defi ciency in rats [2,3,5,16,17] and human beings [ 18]. Alteration in thyroid hormones as suggested by Morley et al [ 1 ] and Fujimoto et al [3] might partly be secondary to deficiency of vitamin A [19] which has been reported to be required for extrathyroidal conversion of T4 to T;, in the liver.…”

Section: Zinc Deficiency and Thyroidmentioning

confidence: 52%

“…Growth retardation due to Zn deficiency in guinea-pigs as observed in the present study has also been reported in other species of animals [14], This might be due to impair ment of DNA synthesis since during Zn defi ciency the enzymes (thymidine kinase and DNA polymerase) and a hormone, somato medin C, required for DNA synthesis have been reported to be decreased [14,15], Sec ondly, hypothyroidism might have also con tributed to growth retardation [14], Lower values of serum T3 and T4 observed in ZnD guinea-pigs of the present study have also been found to be associated with Zn defi ciency in rats [2,3,5,16,17] and human beings [ 18]. Alteration in thyroid hormones as suggested by Morley et al [ 1 ] and Fujimoto et al [3] might partly be secondary to deficiency of vitamin A [19] which has been reported to be required for extrathyroidal conversion of T4 to T;, in the liver. Indeed the interaction between Se and I with respect to T4 and T3 conversion has been reported [20] but a recent study [5] on Zn and I interaction revealed that Zn deficiency did not influence thyroid hor mone metabolism in iodine-deficient rats.…”

Section: Zinc Deficiency and Thyroidmentioning

confidence: 52%

“…In human beings, its defi ciency in natural cases has been reported to influence thyroid status [ 1], but very little work has been done experimentally in guineapigs to prove its role in the functioning of thy roid gland. However, in rats some workers [2][3][4][5] have shown that Zn deficiency decreased serum concentrations of thyroid hormones without indicating any pathological changes in thyroid gland itself. Therefore, taking in view the paucity of the literature on the rela tionship of Zn with thyroid gland, the present work was undertaken in guinea-pigs to study the effect of experimental Zn deficiency on the pathology of thyroid gland and thyroid hormones.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Experimental Zinc Deficiency on Thyroid Gland in Guinea-Pigs

Gupta¹,

Verma²,

Garg³

1997

Ann Nutr Metab

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Zinc deficiency was produced experimentally in guinea-pigs fed on a diet containing 1.03 mg Zn/kg over a period of 45 days. Clinical signs exhibited in Zn-deficient (ZnD) animals were depression with abnormal posture, scaly skin lesions on various parts of the body, oedematous swelling on hind limbs and marked alopecia. There was no effect on food intake. Serum studies in ZnD group revealed significant decreases in the concentrations of Zn from 20 days onwards, and tri-iodo-thyronine (T₃) and thyroxine (T₄) from 30 days onwards. Thyroid glands of ZnD animals were smaller in size and pale or whitish pale in colour. Histopathologically, these glands showed changes of atrophy and degeneration in the follicles. It could be concluded that the depletion in serum T₃ and T₄ due to Zn deficiency was related to thyroid lesions.

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Section: Zinc Deficiency and Thyroidmentioning

confidence: 52%

Section: Zinc Deficiency and Thyroidmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Experimental Zinc Deficiency on Thyroid Gland in Guinea-Pigs

Gupta¹,

Verma²,

Garg³

1997

Ann Nutr Metab

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“…It has been reported that the serum or plasma levels of thyroid hormones were reduced by high Zn intake (Dean et al, 1991;Nishiyama et al, 1994) and were unchanged (Fujimoto et al, 1986) or increased (Oliver et al, 1987) on low Zn intake. In addition, the level of plasma zinc has been found to be correlated with plasma T 3 and T 4 levels (Nishi et al, 1980;Aihara et al, 1984).…”

Section: Discussionmentioning

confidence: 99%

Zinc supplementation decreases total thyroid hormone concentration in small ruminants

Keçeci

Keskin

2002

Acta Veterinaria Hungarica

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The effect of dietary zinc (Zn) supplementation on plasma Zn and serum thyroid hormones was evaluated in healthy male Merino lambs and Angora goats. A total of 12 lambs and 12 goats were divided into two equal groups as control and Zn groups in separate experiments. The lambs and goats of the control groups were fed basal rations alone. The Zn contents of these rations prepared for lambs and goats were 40 mg/kg and 35 mg/kg in dry matter (DM), respectively. Both species of animals in the Zn groups were fed a basal ration supplemented with zinc sulphate adjusted to 250 mg Zn/kg diet in DM. The feeding trial lasted for 12 weeks in lambs and 8 weeks in goats. Blood samples were taken from the jugular vein at 4-week intervals. Both animal species in the Zn groups had higher plasma Zn values than the controls throughout the experimental period, except in the 4th week in goats. However, the levels of serum total thyroxine (T 4 ) and triiodothyronine (T 3 ) were lower in the lambs and goats of the Zn groups, except in the 4th week, as compared to those in the controls. Moreover, serum total thyroid hormone levels of the goats were higher at the 4th week than at the 8th week. Although there was a decrease in the levels of free thyroxine and triiodothyronine of both small ruminant species in the Zn groups when compared to the controls, these alterations were not statistically significant. These results may show that zinc supplementation to the diet at this dose reduces total thyroid hormone levels in small ruminants but does not yet impair the euthyroid status of the organism.

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“…Sympathetic nervous system activity, daily energy intake, physical activity and thyroid hormones are possible modulators of the changes in BMR (Morgan & York, 1983;Fukagawa et al, 1990;Visser et al, 1995;Klausen et al, 1997). Animal (Morley et al, 1980;Fujimoto et al, 1986;Lukaski et al, 1992;Kralik et al, 1996) and human (Wada & King, 1986;Oliver et al, 1987) studies have shown that zinc deficiency is associated with decreases in circulating thyroid hormone levels, in the ratio T3/T4 and in BMR. It is postulated that iodothyronine deiodinase expression is zinc sensitive and that the production of T3 is therefore reduced in zinc deficiency (Lukaski et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

Basal metabolic rate and thyroid hormones of late-middle-aged and older human subjects: the ZENITH study

Meunier

Beattie²,

Ciarapica

et al. 2005

Eur J Clin Nutr

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Objective: This paper describes baseline data on basal metabolic rate (BMR), thyroid hormone levels and body composition of middle-aged and older people participating in the ZENITH project and the correlation of thyroid hormone levels with zinc status. Design: A multicentre prospective intervention study employing a randomised double blind design. Setting: Clermont-Ferrand, Theix (France), Coleraine (Northern Ireland), Grenoble (France), Rome (Italy). Interventions: BMR has been measured on a subsample of 70 middle-aged volunteers (35 men and 35 women recruited in ClermontFerrand, France, aged 55-70 y) and 108 older volunteers (56 men and 52 women recruited in Rome, Italy, aged 70-85 y). Thyroid hormone levels were evaluated in the entire group of ZENITH volunteers (n ¼ 387). BMR was measured by indirect calorimetry. Fatfree mass (FFM) was derived by four skinfold thicknesses using Durnin and Womersley's equations. Concentrations of thyroid hormones (total T3 and T4) were measured using a competitive immunoassay with an enhanced chemiluminescence end point. Results: Italian older volunteers had a significantly lower FFM than middle-aged French volunteers (À7% Po0.01). A negative correlation between BMR and age (men, r ¼ À0.64; women, r ¼ À0.62; both Po0.0001) was observed: BMR was significantly (Po0.000001) lower in Italian elderly volunteers (4.0370.46 kJ/min and 3.2970.42 kJ/min for men and women, respectively) than in middle-aged French volunteers (4.8470.45 kJ/min and 3.8770.38 kJ/min for men and women, respectively), even after adjustment for FFM (À12%). No correlation has been observed between BMR and thyroid hormones both in French and Italian subjects. Total T4 (TT4) concentrations were lowest in middle-aged population (À10%, Po0.0001). A moderate negative correlation has been found with TT4 and red blood cell zinc (r ¼ À0.12, Po0.02, slope À0.026). Conclusions:The results confirm an age-related decline in BMR not entirely explained by body composition or thyroid hormones differences.

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Conversion of Thyroxine into Tri-iodothyronine in Zinc Deficient Rat Liver

Cited by 22 publications

References 0 publications

Effect of Experimental Zinc Deficiency on Thyroid Gland in Guinea-Pigs

Effect of Experimental Zinc Deficiency on Thyroid Gland in Guinea-Pigs

Zinc supplementation decreases total thyroid hormone concentration in small ruminants

Basal metabolic rate and thyroid hormones of late-middle-aged and older human subjects: the ZENITH study

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