Thyroid hormones before and after weight loss in obesity

Abstract

Background: Little is known about changes in thyroid function in obese children. An influence of leptin on thyroid hormone synthesis has been proposed. Aims: To examine thyroid function and leptin concentrations in obese children. Methods: Triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH), and leptin were measured in 118 obese children (aged 4.5-16 years); thyroid function was also determined in 107 healthy children of normal weight. T3, T4, and TSH were analysed in 55 obese children who had achieved weight reduction and in 13 obese children who had not achieved weight reduction after one year based on normal energy diet. Results: TSH, T3, and T4 were significantly higher in obese children compared to those of normal weight. Twelve per cent of the obese children had TSH, 15% had T3, and 11% had T4 concentrations above the twofold standard deviation of normal weight children. The degree of overweight correlated with T3, T4, and TSH. Thyroid hormones did not correlate significantly with leptin. A reduction in overweight showed a significant decrease in T3, T4, and leptin serum concentrations, but there was no significant change in TSH. Conclusion: Peripheral thyroid hormones (T3, T4) and TSH are moderately increased in obese children; weight reduction leads to a long term decrease in the peripheral thyroid hormones but not in TSH. There is no necessity to treat the increased serum TSH.

Free and bound leptin in prepubertal children with Down's syndrome and different degrees of adiposity

“…The observation of elevated plasma sOB-R levels concentrations in children (Kratzsch et al, 2002) and the increased BL fraction, here reported, may contribute to the temporary blockade of the reproductive axis in prepubertal children, which may be overcome, once an increase of FL occurs, in association with an increased adiposity and possibly other factors, giving rise to pubertal development. No relationship between thyroid function and leptin concentrations were found in DS children, as also shown in subjects with congenital hypothyroidism (Asami et al, 2000) and obesity (Reinehr & Andler, 2002), whereas an inverse correlation between leptin and TSH was found in normal children of short stature (Ghizzoni et al, 2001). These discrepancies are similar to those observed in adults with or without thyroid diseases (Corbetta et al, 1997;Valcavi et al, 1997;Korbonits, 1998).…”

Expression of thyrotropin and thyroid hormone receptors in adipose tissue of patients with morbid obesity and/or type 2 diabetes: effects of weight loss

“…On the other hand, this study is one of the few investigations that have unequivocally shown that weight loss leads to a reduction in both TSH and FT 3 levels. 9,10,19,20 Several explanations have been proposed to account for the influence of obesity on thyroid hormones. One suggests that the increased TSH level could reflect pituitary adaptation to increased adiposity through adipokines.…”

“…Finally, it is possible that obesity leads to a state of TSH and thyroid hormone resistance in peripheral tissues. 20 However, information on the tissue expression of genes encoding for TSH and thyroid hormone receptors, and activity of the respective proteins in relation to body weight or diabetes is scarce. TSHRs have been found in rats and in human adipose tissues.…”

Daylong pituitary hormones in morbid obesity: effects of bariatric surgery

“…A slight increase in TSH levels has been reported in adults with moderate obesity and in obese Pituitary hormones and bariatric surgery S Camastra et al children. 17,38,39 In rodents, leptin modulates thyroid hormone production in situations in which energy conservation through a reduction in metabolic rate is required. 40 Such effect appears to occur principally at the level of TRH neurons in the paraventricular hypothalamic nucleus (PVN).…”