Circulating ghrelin in thyroid dysfunction is related to insulin resistance and not to hunger, food intake or anthropometric changes

Abstract

Objective: Ghrelin is a gastric peptide that plays a role in appetite stimulation, energy balance and possibly in insulin resistance. Hyperthyroidism is a situation where negative energy balance and insulin resistance coexist, while in hypothyroidism a positive energy balance and normal insulin sensitivity predominate. We investigated ghrelin levels and their relationship with hunger, food intake and both anthropometric and insulin resistance parameters in patients with thyroid dysfunction. Design and methods: We studied 24 hyperthyroid and 17 hypothyroid patients before and after normalisation of thyroid hormone levels and their respective body mass index (BMI)-matched control group. We measured plasma ghrelin levels, homeostasis model assessment of insulin resistance (HOMA-IR) index, a hunger score, mean three-day calorie intake and anthropometric parameters. Results: In hyperthyroidism, HOMA-IR index was higher (3.21^0.60 vs 1.67^0.15 mM mU/l; P ¼ 0.014, t test for independent data) and ghrelin levels were lower (463.6^36.4 vs 561.1^32.1 pg/ml; P ¼ 0.041, Mann -Whitney U-test) than in its control group and both normalised after treatment (HOMA-IR: 2.28^0.38 mM mU/l; P ¼ 0.106, t test for independent data, and ghrelin: 539.7^45.4 pg/ml; P ¼ 0.549, Mann -Whitney U-test). Glucose, as a component of HOMA-IR index was the only predictor for ghrelin levels (b ¼ 20.415, P ¼ 0.044, stepwise multiple regression analysis). In hypothyroidism, HOMA-IR index and ghrelin levels were similar to those in its control group both before and after treatment. In both thyroid dysfunction states, no correlations were observed between changes in ghrelin levels and in free T4, free T3, anthropometric parameters, total calorie intake and hunger score. Conclusions: In thyroid dysfunction states, ghrelin levels seemed to be in relation to insulin resistance and not to energy balance and food intake regulation, as seen in other physiological and pathological states. European Journal of Endocrinology 153 73-79

Ghrelin in obesity and endocrine diseases

“…In contrast, other studies have found ghrelin levels in hypothyroid patients to be similar to those of healthy subjects and there was no significant change in ghrelin levels after medical treatment of hypothyroidism (Gimenez-Palop et al, 2005;Sadegholvad et al, 2007;Tanda et al, 2009). Anti-parietal cell antibodies and atrophic gastritis has been M a n u s c r i p t 22 detected in patients with autoimmune thyroid disease (Centanni et al, 1999).…”

“…Insulin resistance is increased in hyperthyroidism (Gimenez-Palop et al, 2005) and hyperinsulinaemia has been shown to suppress ghrelin levels (Saad et al, 2002) regardless of thyroid status (Riis et al, 2003).…”

Ghrelin and obestatin in thyroid gland — immunohistochemical expression in nodular goiter, papillary and medullary cancer

“…The relationship between thyroid cancer pathogenesis and ghrelin and obestatin expression has not been clearly defined. Furthermore, since the function of thyroid gland is associated with the maintenance of energy balance, the relationship between ghrelin, obestatin and thyroid function is worthy of consideration [19][20][21][22][23][24].…”

The regulation of circulating ghrelin — with recent updates from cell-based assays [Review]

“…Circulating ghrelin levels are reduced in hyperthyroid patients [157,[207][208][209][210][211]. On the other hand, ghrelin levels were elevated in hypothyroid patients in some reports [212,213], but not in others [207,211,214].…”