Background: Conflicting data exist on the effects of GH replacement therapy (GHRT) on thyroid function and thyroid volume (TV) in GH-deficient (GHD) patients. Aim: The aim of this study was to assess the effects of GHRT on thyroid function and TV in adults with congenital lifetime isolated GHD (IGHD). Subjects and methods: We studied 20 GH-naïve adults with IGHD due to a homozygous mutation of the GHRH-receptor gene at baseline, after 6-month depot-GH replacement therapy (pGH), and 6-month washout (6mo). Total T 3, free T 4 (FT 4), reverse T 3 (rT 3), TSH, IGF-I, SHBG, and TV were measured; body surface area-corrected TV (CTV) was calculated. Results: IGF-I and T 3 increased pGH. T 3 levels remained elevated at 6mo. GHRT did not significantly change FT 4, rT 3, TSH, and SHBG. TV and CTV increased pGH and remained elevated at 6mo. Conclusions: GHRT in IGHD adults caused an increase in serum T 3 levels and TV, suggesting an important role of the GH-IGF-I axis in thyroid function.
- Free thyroxine
- Growth hormone replacement therapy
- Isolated growth hormone deficiency
- Thyroid volume
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism