Objective: GH treatment increases height in Idiopathic Short Stature (ISS), however growth rate differs among patients. Thyroid hormones (TH) are also essential for growth acting through TH receptors (TR) á and â. We reported that GH reduced peripheral TH action in Turner Syndrome. We aimed at assessing the effect of GH treatment in ISS on peripheral TH action and the correlation between thyroid status and growth response
Methods: 18 normal and 25 ISS were evaluated before and after 12 months of life time (normal) or 12 months of GH therapy (ISS). Blood was collected to assess serum markers of peripheral TH action and peripheral blood mononuclear cells for TR mRNA determination by QRT-PCR. Growth parameters were also determined
Results: Although GH treatment did not modify TR mRNA and serum markers of TH action in ISS as a whole group, the individual growth response to GH correlated positively with the change in TRá mRNA level and negatively with TRâ mRNA, TSH and SHBG. The change in each TR mRNA correlated negatively with their basal level
Conclusions: GH therapy induced individual TR changes that correlated with growth velocity. Basal TR mRNA could predetermine the change in TR expression and therefore GH response
