Fat balance and serum leptin concentrations in normal, hypothyroid, and hyperthyroid rats

Iossa, Susanna; Lionetti, Lillà; Mollica, Maria Pina; Crescenzo, Raffaella; Barletta, Antonio; Liverini, Giovanna

doi:10.1038/sj.ijo.0801516

Cited by 38 publications

(49 citation statements)

References 27 publications

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“…Hypothyroid animals had an elevated serum leptin relative to their body weight, which was normalized and even decreased when T3 or T4 were infused. The results were in agreement with 3 other studies (57,59,62) in which hypothyroid rats showed increased leptin mRNA levels and increased leptin secretion, which were acutely reversed by administration of supraphysiological doses of T3 (Table 3).…”

Section: Animal Studiessupporting

confidence: 82%

Circulating leptin and thyroid dysfunction

Zimmermann-Belsing

Brabant²,

Holst³

et al. 2003

Eur J Endocrinol

151

111

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The identification and sequencing of the ob gene and its product, leptin, in 1994 opened new insights in the study of the mechanisms controlling body weight and led to a surge of research activity. Since its discovery, leptin has been the subject of an enormous amount of work especially within the fields of nutrition, metabolism and endocrinology. Leptin is accepted as an adipose signal, and even though the underlying mechanisms are not fully clarified, leptin, in addition to the thyroid hormones, is believed to be involved in regulation during the switch from the fed to the starved state. It is not clear whether leptin and the melanocortin pathways interact with the thyroid axis under physiological conditions other than during starvation or in response to severe illness, both states in which the hypothalamo -pituitary -thyroid axis may be severely suppressed. In addition to the suggested central relationship between leptin and thyroid hormones, there might also be a peripheral relationship although this effect is not clear. Both thyroid hormones and leptin might be involved in the adaptive thermogenesis through mitochondrial uncoupling proteins and heat production because both thyroxine and triiodothyronine are involved in the starvation-induced decrease in thermogenesis. Both rodent and human studies of leptin have failed to show any consistent relationship between thyroid function and serum leptin concentrations. However, leptin might have an important role in thyroid pathophysiology due to thyroid hormone involvement in thermogenesis and regulation of uncoupling proteins. In this review, we have focused on leptin in relation to thyroid pathophysiology.

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Section: Animal Studiessupporting

confidence: 82%

Circulating leptin and thyroid dysfunction

Zimmermann-Belsing

Brabant²,

Holst³

et al. 2003

Eur J Endocrinol

151

111

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“…It has also been reported that insulin secretion is regulated by thyroid hormone (Cortizo et al 1985, Doong et al 1997, and that there is a relationship between serum thyroid hormone levels and diabetes risk (Iossa et al 2001, Crunkhorn & Patti 2008. Hyperthyroidism reduces glucose tolerance in mammals, and the insulin-secretory capacity of the pancreatic islets is reduced by an excess of thyroid hormones (Lenzen & Bailey 1984).…”

Section: Introductionmentioning

confidence: 99%

Impaired insulin secretion from the pancreatic islets of hypothyroidal growth-retarded mice

Taguchi¹,

Tasaki²,

Terakado³

et al. 2010

Journal of Endocrinology

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The growth-retarded (grt) mouse shows thyroid dysfunctionrelated hyporesponsiveness to TSH. Thyroid hormone is a critical regulator of metabolism in many cells; thus, derangement of thyroid function affects many organs and systems. Experiments were conducted focusing on the function of the pancreatic islets in grt mice. We showed occurrence of a fasting hyperglycemia and a decreased plasma insulin level response to a glucose load in grt mice, despite normal insulin molecules being stored in secretory granules of pancreatic islets. We also demonstrated a reduction of insulin secretion in response to glucose administration from islets of grt mice in vitro, while the insulin release in response to KCl stimulation was comparable to that in normal mice, indicating that the isolated islets from grt mice have normal ATPsensitive K C channels and postchannel activity. The mRNA expression levels of glucose transporter 2 and glucokinase in the islets of grt mice were similar to those in normal mice. Triiodothyronine administration to grt mice improved insulin secretion very slightly. On the other hand, mRNA for tyrosylprotein sulfotransferase 2 (Tpst2) was found to be expressed in the pancreatic islets of grt mice. Considering that Tpst2 is the responsible gene of grt mice, mutation of which is associated with a poor function of TSH receptor, the findings raise a possibility of involvement of factors including Tpst2 in the insulin hyposecretion in grt mice.

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“…Furthermore, it is known that increased thyroid activity accompanies increased basal metabolism or vice versa: many thyrotoxic patients show increased physical activity and, conversely, many hypothyroid patients complain of lethargy. e mechanisms through which the thyroid hormone is related to the alterations in energy homeostasis and leads to changes in metabolism and molecular pathways have not been clearly identi ed and remain incompletely understood [4,[26][27][28][29]. In this study, we did not detect a di erence in energy expenditure between patients with hypothyroidism and healthy subjects.…”

Section: Resultsmentioning

confidence: 33%

Evaluation of sleeping energy expenditure using the SenseWear Armband in patients with overt and subclinical hypothyroidism

Ulaş

Büyükhatipoğlu²,

Eren³

et al. 2012

CIM

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Purpose: e aim of the present study was to evaluate the average sleeping energy expenditure (EE) levels using the SenseWear Armband (SWA) in patients with overt and subclinical hypothyroidism.Methods: Sixty patients with hypothyroidism and 30 healthy individuals were recruited for the study. Hypothyroid patients were divided into two groups: group 1 (n = 30) consisted of patients with overt hypothyroidism and group 2 (n = 30) consisted of patients with subclinical hypothyroidism. Lastly, group 3 (n = 30) consisted of healthy subjects.e average EE and metabolic equivalent of task (MET) values during sleep of all the hypothyroid participants were analyzed at baseline and at the end of the study. Data were also obtained from the healthy subjects at baseline.Results: e average sleeping EE and METs values were not signi cantly di erent at baseline. Similarly, these values did not change signi cantly a er achieving a euthyroid state via thyroid hormone replacement (both p > 0.05). Conclusions:Contrary to what has been previously reported , the average sleeping EE and METs values in all hypothyroid patients and healthy individuals were similar at baseline and did not change in the patients with overt and subclinical hypothyroidism a er achievement of a euthyroid state.

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Fat balance and serum leptin concentrations in normal, hypothyroid, and hyperthyroid rats

Cited by 38 publications

References 27 publications

Circulating leptin and thyroid dysfunction

Circulating leptin and thyroid dysfunction

Impaired insulin secretion from the pancreatic islets of hypothyroidal growth-retarded mice

Evaluation of sleeping energy expenditure using the SenseWear Armband in patients with overt and subclinical hypothyroidism

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