Circulating leptin and thyroid dysfunction

Zimmermann-Belsing, Tina; Brabant, Georg; Holst, Jens J.; Feldt‐Rasmussen, Ulla

doi:10.1530/eje.0.1490257

Cited by 150 publications

(131 citation statements)

References 95 publications

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“…In humans, concentrations of circulating progesterone have been correlated to plasma leptin during the menstrual cycle (Hardie et al, 1997) but, in the current study, progesterone concentrations were not different between the ewes fed the high-salt diet and the ewes fed the control diet. Another factor that decreases leptin secretion is an increase in energy expenditure (Zimmermann-Belsing et al, 2003). However, in the present study there was not a large difference in plasma T 3 concentration between ewes fed high salt and control animals, suggesting that energy expenditure was similar between the two groups.…”

contrasting

confidence: 63%

Reproductive capacity of Merino ewes fed a high-salt diet

Digby

Masters

Blache

et al. 2008

Animal

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An option to increase the productivity of saline land is to graze sheep on salt-tolerant plants, which, during the summer/ autumn period, can contain 20% to 25% of their dry matter as salt. This study assessed the impact of coping with high dietary salt loads on the reproductive performance of grazing ewes. From the time of artificial insemination until parturition, 2-year-old maiden Merino ewes were fed either a high-salt diet (NaCl 13% of dry matter) or control diet (NaCl 0.5% of dry matter). Pregnancy rates, lamb birth weights, milk composition and the plasma concentrations of hormones related to salt and water balance, and energy metabolism were measured. Leptin and insulin concentrations were lower (1.4 6 0.09 v. 1.5 6 0.12 ng/ml; (P , 0.05) and 7.2 6 0.55 v. 8.2 6 0.83 ng/ml; P , 0.02) in response to high-salt ingestion as was aldosterone concentration (27 6 2.7 v. 49 6 5.4 pg/ml; P , 0.05), presumably to achieve salt and water homeostasis. Arginine vasopressin concentration was not significantly affected by the diets, but plasma concentration of T 3 differed during gestation (P , 0.02), resulting in lower concentrations in the high-salt group in the first third of gestation (1.2 6 0.18 v. 1.3 6 0.14 pmol/ml) and higher concentrations in the final third of gestation (0.8 6 0.16 v. 0.6 6 0.06 pmol/ml). T 4 concentration was lower in ewes ingesting high salt for the first two-thirds of pregnancy (162 6 8.6 v. 212 6 13 ng/ml; P , 0.001). No substantial effects of high salt ingestion on pregnancy rates, lamb birth weights or milk composition were detected.Keywords: aldosterone, high salt, insulin, leptin, reproduction IntroductionSalinity is an increasing problem in agriculture worldwide (Ghassemi et al., 1995) and the use of halophytic plants such as saltbush represents one of the few options available to revegetate salinised landscapes and re-establish grazing systems . Some landholders in Australia are grazing sheep on saltbush to fill a summer/ autumn feed gap (Masters et al., 2006), a period that coincides with the greater demands of late pregnancy for autumn-or winter-lambing ewes. However, feeding saltbush may possibly have a negative impact on reproductive performance of the ewes as high salt intake may reduce intake and cause physiological changes associated with adaptation to the salt load.High salt intake has been shown to reduce voluntary feed intake (Masters et al., 2005;Blache et al., 2007) as well as the efficiency of energy use for production (Arieli et al., 1989) in sheep. A decrease either in voluntary feed intake or in fat reserves is usually associated with a decrease in the concentration of metabolic hormones such as insulin and leptin (Chilliard et al., 2005) and recently a high salt ingestion has been shown by Blache et al. (2007) to affect energy metabolism through changes in insulin concentrations in sheep fed high salt (20% NaCl) diets. Thus, the ingestion of large amount of salt may impact energy availability and consequently reproductive performance.There are also physiological 'con...

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contrasting

confidence: 63%

Reproductive capacity of Merino ewes fed a high-salt diet

Digby

Masters

Blache

et al. 2008

Animal

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“…Apart from modulating food intake and energy expenditure, leptin acts as a neuroendocrine regulator of the hypothalamic-pituitary-thyroid axis by regulating the expression of TRH in the paraventricular nucleus; leptin secretion by adipose tissue will then be stimulated by TSH (Menendez et al 2003, Oge et al 2005, Feldt-Rasmussen 2007, Santini et al 2010. Leptin may also affect deiodinases, activating the T 4 to T 3 conversion (Zimmermann-Belsing et al 2003, Reinehr 2010. In addition to the association between TSH and BMI, there is a clinical association between higher serum TSH levels and an increased risk of malignancy in human thyroid nodules (Fiore & Vitti 2012) and advanced stage of the disease (McLeod et al 2013).…”

Section: Thyroid Hormonesmentioning

confidence: 99%

Obesity and thyroid cancer

Marcello,

Cunha,

Batista

et al. 2014

Endocrine Related Cancer

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Many studies have provided observational data on the association of obesity and thyroid cancers, but only few of them propose mechanisms that would permit a better understanding of the causal molecular mechanisms of this association. Considering that there is an increasing incidence of both obesity and thyroid cancers, we need to summarize and link recent studies in order to characterize and understand the contribution of obesity-related factors that might affect thyroid cancer development and progression. Adipose tissue is involved in many vital processes, including insulin sensitivity, angiogenesis, regulation of energy balance, activation of the complement system, and responses such as inflammation. Although these processes have their own molecular pathways, they involve the same molecules through which obesity and adipose tissue might exert their roles in carcinogenesis, not only affecting MAPK and PI3K or even insulin pathways, but also recruiting local inflammatory responses that could result in disease formation and progression. This review describes five important issues that might explain the link between excessive weight and thyroid cancer: thyroid hormones, insulin resistance, adipokines, inflammation, and sexual hormones.

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“…In addition to its role in regulating body weight, leptin signals to the CNS the transition from the fed to fasted state (for review see [70]). …”

Section: Leptin and The Hpt Axismentioning

confidence: 99%