Dexamethasone Suppression of Serum T<sub>3</sub>and T<sub>4</sub>

DeGroot, Leslie J.; Hoye, Kathleen

doi:10.1210/jcem-42-5-976

Cited by 66 publications

(23 citation statements)

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“…The effect on thyroid function has been previously described in humans (Wilber and Utiger 1969;Faglia et al 1973;Degroot and Hoye 1976) and in rats (Ranta 1975). The reduction in thyroxine secretion is probably due to a direct action on the pituitary and on the thyroid.…”

Section: Discussionmentioning

confidence: 74%

Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Ba¹,

Wallace²

1978

Aust. Jnl. Of Bio. Sci.

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Plasma concentrations of dexamethasone have been measured in sheep during an 8-day infusion of dexamethasone-21-phosphate. The dexamethasone concentration profiles generally revealed a reproducible pattern with three phases-a peak during the first 48 h infusion which was followed by falling concentrations during the next 5 days, and a small increase in dexamethasone concentration during the final 24 h infusion was not uncommon. The pattern of dexamethasone concentrations was retained when dosage was arranged in such a way as to infuse increasing quantities of hormonal analogue as infusion progressed. Aspects of the metabolism of the analogue are discussed.Endogenous thyroxine and cortisol were significantly depressed during infusion. In these experiments wool was completely shed in three out of four animals dosed at a rate of 8·5 mg dexamethasone/kg o · 75 • The recovery of wool growth to its pretreatment values occurred by about one month after infusion. The consumption of food and body weight increases were satisfactory during the post-infusion period.

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Section: Discussionmentioning

confidence: 74%

Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Ba¹,

Wallace²

1978

Aust. Jnl. Of Bio. Sci.

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“…This may be due to the relative amelioration of glucocorticoid deficiency by relieving acute stress mainly caused by infection, as observed previously by Dexter [18]. Although pharmacological doses of glucocorticoids have been reported to depress serum T3 in man [17,19] and to inhibit iodide uptake into FRTL-5 rat thyroid cells [9], this case as well as cases in the literature may indicate that a physiological dose of glucocorticoid is needed for the synthesis or secretion of thyroid hormone under stimulation by TSH. Furthermore, none of the patients with a normal pituitary-thyroid axis was reported as possessing antithyroid antibodies, whereas cases with pituitary-thyroid abnormality had a high incidence of these antibodies (Table 2).…”

Section: Discussionmentioning

confidence: 75%

Thyroid Dysfunction in isolated Adrenocorticotropic Hormone (ACTH) Deficiency: Case Report and Literature Review.

et al. 1993

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Abstract. A case of isolated ACTH deficiency accompanying transient primary hypothyroidism was reported along with a review of literature on isolated ACTH deficiency in Japan with special reference to its association with thyroid function. Our case, a 56-year-old woman, developed somnolence and hypoglycemia due to isolated ACTH deficiency. She also had the features of hypothyroidism, namely mounding phenomenon, muscle rigidity, increased plasma myogenic enzymes and cold intolerance. Both free T3 and free T4 were decreased, and basal as well as TRH-stimulated TSH levels were abnormally high. Plasma thyroglobulin was increased and no anti-thyroid antibodies were detected. All thyroid related physical and biochemical abnormalities disappeared after hydrocortisone replacement. A review of the literature on 103 cases disclosed that more than half the cases with isolated ACTH deficiency had a high plasma level of TSH, basal and/or TRH-induced, while the antithyroid antibodies were reported to be positive in only 13 cases. In more than 70% of such cases, the abnormality in the pituitary-thyroid axis was transient and was reversed by glucocorticoid replacement. Our case and cases in the literature indicate that the interference of thyroid hormone synthesis and/or secretion by glucocorticoid deficiency per se is the major cause of thyroid dysfunction rather than associated autoimmune thyroid disease.

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“…propylthiouracil (23,24), glucocorticoids in high doses (25)(26)(27), certain radiographic contrast media (28,29), and the beta adrenergic blocking agents, propranolol (30) and amiodarone (31). It has generally been assumed that all of these factors act primarily to decrease production of T3 from T4, rather than to increase peripheral degradation ofT3, and direct studies have shown this to be true in the case of cirrhosis (5,22), fasting (12,32), and diabetes (15).…”

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confidence: 99%

Observations on the factors that control the generation of triiodothyronine from thyroxine in rat liver and the nature of the defect induced by fasting.

Balsam¹,

Ingbar²

1979

J. Clin. Invest.

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A B S T R A C T Studies were performed to explore the mechanism underlying the impaired generation of 125-I-3,5,3'-triiodothyronine (T3) from 1251-thyroxine (T4) (T3-neogenesis) in preparations of liver from rats fasted for 48 h and the prevention of this effect by the feeding of glucose. T3-neogenesis in livers from fasted animals and those fed chow or glucose was assessed in various mixtures of crude microsomal fractions with either buffer or cytosols. T3-neogenesis was mediated by an enzyme present in the microsomal fraction whose activity was enhanced by cytosolic cofactor(s). In livers from animals fasted for 48 h, the supporting activity of cytosol was decreased, whereas the activity of the enzyme was unaffected. Administration of glucose as the sole nutritional source prevented the decrease in the supporting activity of hepatic cytosol that was regularly observed in the case of animals totally deprived of food.The diminished supporting activity for T3-neogenesis provided by liver cytosol from fasted animals was restored to normal by enrichment with either NADPH or GSH, but the two cofactors appeared to act at different loci. GSH stimulated T3-neogenesis in microsomes incubated in the absence of cytosol, i.e., in buffer, whereas NADPH did not. The stimulatory effect of both agents was blocked by the sulfhydryl oxidant, diamide, which also inhibited T3-neogenesis in mixtures of microsomes with cytosols. Taken together, these observations suggest that GSH acts directly on the enzyme in the crude microsomal fraction, whereas NADPH acts within the cytosol, possibly by increasing the concentration of GSH through the action of the enzyme glutathione reductase, for which NADPH is a cofactor. In this light, the decreased supporting activity of hepatic cytosol

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Dexamethasone Suppression of Serum T₃and T₄

Abstract: Dexamethasone (2 mg q6h for 48 h) decreased serum T3 in normal and athyreotic subjects, and decreased T4 in normal subjects. Dexamethasone probably alters secretion and peripheral metabolism of thyroid hormones.

Cited by 66 publications

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Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Thyroid Dysfunction in isolated Adrenocorticotropic Hormone (ACTH) Deficiency: Case Report and Literature Review.

Observations on the factors that control the generation of triiodothyronine from thyroxine in rat liver and the nature of the defect induced by fasting.

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Dexamethasone Suppression of Serum T3and T4

Abstract: Dexamethasone (2 mg q6h for 48 h) decreased serum T3 in normal and athyreotic subjects, and decreased T4 in normal subjects. Dexamethasone probably alters secretion and peripheral metabolism of thyroid hormones.

Cited by 66 publications

References 0 publications

Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Thyroid Dysfunction in isolated Adrenocorticotropic Hormone (ACTH) Deficiency: Case Report and Literature Review.

Observations on the factors that control the generation of triiodothyronine from thyroxine in rat liver and the nature of the defect induced by fasting.

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Dexamethasone Suppression of Serum T₃and T₄