Low Serum Triiodothyronine (T<sub>3</sub>) and Hypothyroidism in Anorexia Nervosa

Croxson, Michael; Ibbertson, H. K.

doi:10.1210/jcem-44-1-167

Cited by 115 publications

(46 citation statements)

References 21 publications

(22 reference statements)

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“…Alterations of the thyroid axis in malnutrition are controversial (24). In our study, T 3 levels were low at the beginning of treatment, within the low limits of normality during 1 year of treatment and were normalized after the follow-up period.…”

Section: Discussionmentioning

confidence: 39%

The effects of estrogen administration on bone mineral density in adolescents with anorexia nervosa

M¹,

Morandé

Garcia-Centenera

et al. 2002

Eur J Endocrinol

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Objective: Profound osteopenia is a serious complication of anorexia nervosa (AN). The aim of this work was to study the effect of prolonged AN on lumbar spine bone mineral density (BMD) and to determine whether oral estrogen administration prevents bone loss in women with this disorder. Subjects and Methods: Thirty-eight amenorrheic women with AN (mean age: 17.3 years) were treated with estrogen (50 mg of ethinyl estradiol) and gestagen (0.5 mg of norgestrel) during 1 year. Clinical variations, biochemical indices and BMD were studied at three different time points, including after a period of amenorrhea of at least 12 months ðn ¼ 38Þ, after the administration of estrogens for 1 year ðn ¼ 22Þ, and after a 1-year follow-up period ðn ¼ 12Þ. Results: Initial mean BMD was significantly lower than normal (22:1^0:8 S.D.) and less than 22.5 S.D. below normal in 38% of the women with AN. The estrogen-treated group had no significant change in BMD even after the follow-up period and partial recovery of weight. Estradiol and total IGF-I levels were significantly lower throughout the study. All subjects had normal thyroxine (T 4 ) and TSH levels and calcium metabolism. However, total tri-iodothyronine (T 3 ) was decreased in all anorexic subjects in the first and second study points and were within normal limits after the follow-up period. Conclusions: (1) Estrogen replacement alone cannot prevent progressive osteopenia in young women with AN. (2) Other factors, such as the loss of weight, the duration of the amenorrhea and the low levels of total insulin-like growth factor-I (IGF-I) could contribute to the loss of bone mass in women with this disorder.

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Section: Discussionmentioning

confidence: 39%

The effects of estrogen administration on bone mineral density in adolescents with anorexia nervosa

M¹,

Morandé

Garcia-Centenera

et al. 2002

Eur J Endocrinol

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“…An alternative explanation for the development of left ventricular dysfunction might relate to the previously reported high incidence of hypothyroidism. 35 However, several recent studies in patients with anorexia nervosa have demonstrated that thyroxine (T4) and thyroid-stimulating hormone (TSH) levels are normal and that tri-iodothyronine (T3) is adaptively down-regulated proportional to the reduction in body weight, which thus spares muscle wasting and does not indicate the presence of hypothyroidism.A3t3 Moreover, all our patients were both clinically and biochemically euthyroid.…”

Section: Discussionmentioning

confidence: 99%

Effects of reduced left ventricular mass on chamber architecture, load, and function: a study of anorexia nervosa.

Sutton¹,

Plappert²,

Crosby³

et al. 1985

Circulation

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“…As judged from concentrations of T3 and rT3 in serum, such shifts do indeed occur. A diversity of conditions has been shown to be associated with decreases in serum T3 concentration, among them starvation (3-6), acute or severe chronic illness (7,8), operative stress (9,10), anorexia nervosa (11)(12)(13), and the administration ofglucocorticoids (14)(15)(16), the adrenergic blocking agents amiodarone (17), or propranolol (18), or propylthiouracil (PTU) (19,20). In many ofthese situations there occurs an accompanying increase in serum rT3 concentration (4,6,8,15,17 tissues obtained from Sprague-Dawley rats of the CD strain (Charles River Breeding Laboratories, Wilmington, Mass.).…”

mentioning

confidence: 99%

“…10 or 20 ,ul of extract was rapidly evaporated under nitrogen, the T3 was solubilized in rat serum freed of T3 by charcoal adsorption, and the T3 content was assayed. Preliminary studies indicated that [10][11][12][13][14][15][16][17][18][19][20] j1 of tissue extract incubated without substrate T4 could be introduced into the radioimmunoassay without influencing the configuration ofthe standard curve. Negligible generation ofT3 from T4 was detected in simultaneously incubated tissuefree blanks.…”

mentioning

confidence: 99%

The Influence of Fasting, Diabetes, and Several Pharmacological Agents on the Pathways of Thyroxine Metabolism in Rat Liver

Balsam¹,

Ingbar²,

Sexton³

1978

J. Clin. Invest.

173

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A B S T R A C T As judged from both paper and column chromatography, slices or homogenates of liver from rats fasted for 48 h displayed a lesser rate of generation of 1251-labeled 3,5,3'-triiodothyronine (T3) from 1251-labeled thyroxine (T4) added to incubation media than did preparations from normal chow-fed animals. A similar defect in the conversion of T4 to T3 in the livers of fasted animals was observed when preparations were incubated with substrate concentrations of T4 so that T3 generation could be assessed by radioimmunoassay. The effect offasting could be prevented, wholly or in part, by administration of glucose in the drinking water to otherwise fasted animals, and the degree ofprevention appeared to be proportional to the concentration of glucose employed. Diminished generation of T3 from T4 was similarly evident in the livers of animals with streptozotocin-induced diabetes mellitus, and this defect was overcome by the provision of insulin in vivo, but not in vitro. Decreased formation of T3 from T4 was also observed in preparations of liver from animals given dexamethasone, amiodarone, and propylthiouracil. In no case could these effects on the net formation of T3 from T4 be explained by effects of the experimental conditions on the degradation of the T3 generated, as judged from the rate of degradation of exogenous 125I-T3 measured in parallel incubates.An analysis of the rate of disappearance of 125I-T4 from reaction mixtures in relation to the rate of appearance of 125I-T3 and 1251-iodide was employed to estimate the activity of the 5-monodeiodinating pathway of T4 metabolism that leads to the formation of 3,3',5'-triiodothyronine (reverse T3). Such estimates indicated that reverse T3 formation was actively proceeding in the preparations studied, was slightly enhanced by Received for publication 9 November 1977 and in revised form 14 March 1978. fasting, was unaffected by dexamethasone and amiodarone, and was markedly inhibited by propylthiouracil.In view ofthe similarities between the effect ofthese experimental manipulations on the generation of T3 from T4 by rat liver in vitro to their effects on the production rates and serum concentrations of T3 in man, it is concluded that the rat liver system provides a suitable model for the study of factors that influence the conversion of T4 to T3 in man. In addition, the findings strongly indicate that this process, at least in the liver, is closely linked to the utilization of carbohydrate. INTRODUCTION Recent studies have provided convincing evidence that 3,5,3'-triiodothyronine (T3)l contributes a major portion to the overall metabolic action of the thyroid hormones within the peripheral tissues. It is evident, moreover, that much of the T3 found in the blood of normal man arises, not by direct secretion from the thyroid gland, but rather from the peripheral monodeiodination of thyroxine (T4) in its outer ring at the 5'-position. It is generally agreed that this reaction results in activation of the hormone molecule, as T3 is several times more ...

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Low Serum Triiodothyronine (T₃) and Hypothyroidism in Anorexia Nervosa

Cited by 115 publications

References 21 publications

The effects of estrogen administration on bone mineral density in adolescents with anorexia nervosa

The effects of estrogen administration on bone mineral density in adolescents with anorexia nervosa

Effects of reduced left ventricular mass on chamber architecture, load, and function: a study of anorexia nervosa.

The Influence of Fasting, Diabetes, and Several Pharmacological Agents on the Pathways of Thyroxine Metabolism in Rat Liver

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Low Serum Triiodothyronine (T3) and Hypothyroidism in Anorexia Nervosa

Cited by 115 publications

References 21 publications

The effects of estrogen administration on bone mineral density in adolescents with anorexia nervosa

The effects of estrogen administration on bone mineral density in adolescents with anorexia nervosa

Effects of reduced left ventricular mass on chamber architecture, load, and function: a study of anorexia nervosa.

The Influence of Fasting, Diabetes, and Several Pharmacological Agents on the Pathways of Thyroxine Metabolism in Rat Liver

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Low Serum Triiodothyronine (T₃) and Hypothyroidism in Anorexia Nervosa