Progressive normalization of growth hormone-binding protein and IGF-I levels in treated growth hormone-deficient children
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J Leger1, M Noel, P Czernichow
1Department of Pediatric Endocrinology and Diabetes, Hopital Robert Debré, Paris, France.
Insights
Human growth hormone (hGH) treatment in children with GH deficiency initially lowers growth hormone-binding protein (GHBP) then gradually increases it over 12 months, supporting GH
Area of Science:
- Pediatric Endocrinology
- Hormone Therapy
- Growth Disorders
Background:
- Growth hormone (GH) deficiency impacts childhood growth.
- Growth hormone-binding protein (GHBP) is a key regulator in the GH axis.
- Understanding GHBP dynamics during treatment is crucial.
Purpose of the Study:
- To investigate the short- and long-term effects of human growth hormone (hGH) therapy on GHBP levels in prepubertal children with GH deficiency.
- To analyze the temporal relationship between hGH treatment, GHBP changes, and insulin-like growth factor I (IGF-I) levels.
- To assess the correlation between GHBP and IGF-I increases with growth velocity.
Main Methods:
- Study included 18 prepubertal children with isolated idiopathic GH deficiency.
- GHBP and IGF-I levels were measured before and during 24 months of daily hGH therapy (0.6 IU/kg/wk).
- Statistical analysis compared pretreatment values with levels at various treatment intervals.
Main Results:
- Pretreatment GHBP levels were significantly lower than in normal children.
- An initial transient decrease in GHBP was observed 6 hours after the first hGH injection.
- GHBP levels gradually increased during hGH therapy, becoming significantly higher after 12 months.
- IGF-I levels normalized within 3 months of hGH therapy.
- No significant correlation was found between GHBP/IGF-I increases and growth velocity.
Conclusions:
- hGH therapy plays a role in regulating GHBP in humans.
- The effect of GH on GHBP is progressive and variable over time.
- GHBP changes do not directly correlate with growth response in this cohort.
Abstract:
The short- and long-term effects of hGH treatment on growth hormone (GH)-binding protein (GHBP) were examined in 18 prepubertal children, aged 1.5-10 y, with isolated idiopathic GH deficiency. The patients were studied before and at regular intervals during 24 mo of hGH therapy (0.6 IU/kg/wk, given daily). Pretreatment GHBP values were low: 14.6 +/- 1.2% of radioactivity (p < 0.0001 versus normal prepubertal children). After the first hGH injection, GHBP levels fell significantly at 6 h (8.2 +/- 1.3% of radioactivity) and then remained at basal level during the first week. Under hGH therapy, an increase in GHBP was observed, but it occurred at different times of treatment, from 1 to 12 mo, and the mean GHBP value became significantly higher than the value before treatment after 12 mo of therapy. An increase in serum IGF-I level was observed as soon as 1 wk of hGH therapy, and after 3 mo, the mean IGF-I value was normal. No correlation was found between the increase in GHBP, IGF-I levels, and the growth velocity at 12 and 24 mo of treatment. These findings support the role of GH in the regulation of GHBP/receptor in man. The time course of the GH effect appears to be progressive and variable.