title: Successful treatment of thyrotoxicosis is accompanied by a decrease in serum sclerostin levels.
abstract: Sclerostin, a product of a SOST gene, is a protein expressed by osteocytes that inhibits osteoblastic bone formation. Several hormones, including PTH and glucocorticosteroids, have been suggested to be possible regulators of sclerostin production. The influence of thyroid hormones on sclerostin synthesis has not been investigated, so far. The aim of the study was to evaluate sclerostin concentrations in patients before and after treatment of thyrotoxicosis.
  
  
  METHODS
  The study involved 15 patients (4 men), mean age 51.8±15.3 years, mean BMI value - 24.7±3.5, with thyrotoxicosis due to Graves' disease or toxic multinodular goitre. Serum sclerostin was measured by immunoassay at diagnosis of thyrotoxicosis and after 6-10 weeks of treatment with thiamazole. The data were analysed by means of simple descriptive statistics of location and dispersion and Mann-Whitney U test for pairs of results, before and after thiamazole therapy. Association between variables was evaluated with use of Spearman`s correlation coefficient.
  
  
  RESULTS
  There was a significant decrease in free T3 (FT3) and free T4 (FT4) concentrations (from 8.74±4.79 pg/ml to 3.54±2.40 pg/ml, and from 4.48±2.21 ng/ml to 1.02±1.07 ng/ml, respectively, p<0.001). This was accompanied by a marked decrease of serum sclerostin levels from 55.46±20.90 pmol/l to 35.73±15.70 pmol/l, p<0.0015). Interestingly, enough, sclerostin levels did not correlate with serum FT3 or FT4 concentrations.
  
  
  CONCLUSIONS
  Restoration of a euthyroid state in patients with thyrotoxicosis results in a significant decrease in serum sclerostin concentrations. The above mentioned phenomenon may reflect lowering of bone metabolism, but a possible direct influence of thyroid hormones on SOST gene needs to be investigated.
authors.affiliation: Department of Endocrinology and Metabolic Diseases, Polish Mother's Memorial Hospital - Research Institute, Rzgowska St, No, 281/289, 93-338, Lodz, Poland. alewin@csk.umed.lodz.pl.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Skowrońska-Jóźwiak
authors.forename: Kinga
authors.initials: K
authors.lastname: Krawczyk-Rusiecka
authors.forename: Krzysztof C
authors.initials: KC
authors.lastname: Lewandowski
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Adamczewski
authors.forename: Andrzej
authors.initials: A
authors.lastname: Lewiński