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


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 mMmU/l; P = 0.014, t test for independent data) and ghrelin levels were lower (463.6 +/- 36.4 vs 561.1 +/- 32.1 pg/ml; P = 0.041, Mann-Whitney U-test) than in its control group and both normalised after treatment (HOMA-IR: 2.28 +/- 0.38 mMmU/l; P = 0.106, t test for independent data, and ghrelin: 539.7 +/- 45.4 pg/ml; P = 0.549, Mann-Whitney U-test). Glucose, as a component of HOMA-IR index was the only predictor for ghrelin levels (beta = -0.415, P = 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.
Unit of Diabetes Endocrinology and Nutrition, Hospital de Sabadell, Sabadell, Spain.
Olga
O
Giménez-Palop
Gabriel
G
Giménez-Pérez
Dídac
D
Mauricio
Eugenio
E
Berlanga
Neus
N
Potau
Carme
C
Vilardell
Jaume
J
Arroyo
José-Miguel
JM
González-Clemente
Assumpta
A
Caixàs
D000328:Adult; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D004435:Eating; D004734:Energy Metabolism; D005260:Female; D054439:Ghrelin; D006706:Homeostasis; D006801:Humans; D006815:Hunger; D006980:Hyperthyroidism / Q000175:diagnosis / Q000378:metabolism*; D007037:Hypothyroidism / Q000175:diagnosis / Q000378:metabolism*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D036361:Peptide Hormones / Q000097:blood*; D011237:Predictive Value of Tests; D013961:Thyroid Gland / Q000502:physiology
D015415:Biomarkers; D001786:Blood Glucose; D054439:Ghrelin; D036361:Peptide Hormones