[Analysis of serum levels of ghrelin and obestatin in children and adolescents with autoimmune thyroid diseases].
INTRODUCTION
Thyroid disease is leading to a change of weight - in hyperthyroidism body mass is reduced, but in hypothyroidism it is increased. Recently researches suggest that many new bioactive substances, like ghrelin and obestatin, play a role in regulation of body mass. These closely related hormones have different effects- ghrelin increases, but obestatin decreases the appetite. The aim of the study was to evaluate ghrelin and obestatin levels in young patients with untreated Graves' disease, subclinical Hashimoto' thyroiditis and in children with nodular goiter in the euthyroid clinical state.


MATERIAL AND METHODS
The study group formed 78 patients of the Outpatient Endocrinology of the 2nd Department of Children's Disease (Medical University in Bialystok) and Outpatient Endocrinology IHC in Warsaw suffering from Graves' disease (29 girls and 2 boys; aged from 6 to 21 - mean 15,2 yrs) and Hashimoto's thyroiditis (29 girls and 3 boys; aged from 9 to 18 - mean 14,5 yrs). The control group consisted of children with nodular goiter (euthyroid) - 13 girls and 2 boys; aged from 9 to 18 - mean 14,8 yrs. In all patients, ghrelin and obestatin levels were analyzed by RIA's method (Phoenix Pharmaceuticals, USA).


RESULTS
In children and adolescents with hyperthyroidism in Graves' disease we found lower levels of ghrelin compared to the group of children with nodular goiter and with subclinical hypothyroidism in Hashimoto's thyroiditis (123+/-23 vs. 151+/-45; vs. 140+/-36 pg/ml, p<0,02, ns). On the other hand obestatin levels were lower in children with untreated subclinical hypothyroidism in Hashimoto's thyroiditis compared to a group with nodular goiter or Hashimoto's thyroiditis in euthyroidism (203,28+/-59 vs. 222.49+/-49; 267.24+/-70 pg/ml, p<0.03, p<0.02). In a group of untreated hyperthyroidism in Graves' disease we found correlations between ghrelin and fT3 (r=-0.36, p<0,4) and fT4 levels (r=- 0.45, p<0.01).


CONCLUSIONS
In conclusion, we suggested that disturbances in thyroid hormones in thyroid diseases have an essential effect on changes of hormones controlled appetite: ghrelin (in hyperthyroidism) and obestatin (in hypothyroidism).