Growth Hormone Treatment in Children with Idiopathic Short Stature: Correlation of Growth Response with Peripheral Thyroid Hormone Action

S. SUSPERREGUY, L. MUÑOZ, N. TKALENKO, I.D. MASCANFRONI, V.A. ALAMINO, M.M. MONTESINOS, A.M. MASINI-REPISO, M.B. MIRAS, C.G. PELLIZAS

Costa do Sauipe

Encuentro; XXI Annual Meeting, SLEP; 2007

SLEP

ABSTRACT 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) α and β. 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 thy- roid 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 param- eters 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 posi- tively with the change in TRα mRNA level and negatively with TRβ mRNA, TSH and SHBG. The change in each TR mRNA correlated negatively with their basal levels. 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.