Growth hormone bioactivity and immunoactivity in tall children

Mauro Bozzola, G. Radetti, F. Buzi, G. Tonini, A. Moretta, M. Autelli, A. Aglialoro, G. Rondini, A. Barreca

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

In subjects with constitutional tall stature, both low and high GH response to stimulation tests have been observed when measured by commercial kits. To investigate the reason for these conflicting results, we evaluated growth hormone (GH) secretion using different assays as well as GH-binding protein and insulin-like growth factor-I (IGF-I) concentrations in tall children. Serum samples were collected from 22 prepubertal constitutionally tall children, aged 2.87-13.25 years, during two pharmacological tests to evaluate serum GH levels measured by both immunofluorometric assay (IFMA) and the Nb2 cell bioassay. Serum IGF-I values were evaluated by RIA. Circulating low affinity (LA) and high affinity (HA) GH-binding proteins (GHBPs) were evaluated by FPLC gel filtration. Considering the highest serum GH levels as measured by IFMA, the 22 tall subjects were divided into two groups: group A including 16 children with blunted serum GH peak levels (5.78 ± 0.68 ng/ml) and group B including 6 subjects with normal serum GH peak values (15.73 ± 1.56 ng/ml). No differences were observed in serum GH peak levels as measured by the Nb2 cell bioassay between group A (14.77 ± 1.54 ng/ml) and group B (16.03 ± 1.96 ng/ml), and between both groups and 11 age-and sex-matched controls (12.25 ± 1.19 ng/ml). In group A, the Nb2 cell bioassay/IFMA ratio of serum GH peak levels (0.29 ± 0.08) was significantly higher (p <0.05) than in group B (0.07 ± 0.01). No differences were found in serum LA-GHBP and HA-GHBP as well as in IGF-I concentrations between the 16 patients of group A and the 6 of group B. Likewise, no difference in auxological parameters was found between the two groups. The biological activity of GH evaluated using the Nb2 cell bioassay is similar in tall children with a low GH response as measured by IFMA in comparison with those with a normal GH response, and is in agreement with both the auxological data and serum IGF-I concentrations.

Original languageEnglish
Pages (from-to)541-546
Number of pages6
JournalJournal of Endocrinological Investigation
Volume22
Issue number7
Publication statusPublished - 1999

Fingerprint

Growth Hormone
Fluoroimmunoassay
Serum
Insulin-Like Growth Factor I
Biological Assay
Gel Chromatography
Age Groups
Pharmacology
somatotropin-binding protein

Keywords

  • Growth hormone
  • Growth hormone binding protein
  • Growth hormone bioactivity
  • Insulin-like growth factor-I
  • Tall stature

ASJC Scopus subject areas

  • Endocrinology

Cite this

Bozzola, M., Radetti, G., Buzi, F., Tonini, G., Moretta, A., Autelli, M., ... Barreca, A. (1999). Growth hormone bioactivity and immunoactivity in tall children. Journal of Endocrinological Investigation, 22(7), 541-546.

Growth hormone bioactivity and immunoactivity in tall children. / Bozzola, Mauro; Radetti, G.; Buzi, F.; Tonini, G.; Moretta, A.; Autelli, M.; Aglialoro, A.; Rondini, G.; Barreca, A.

In: Journal of Endocrinological Investigation, Vol. 22, No. 7, 1999, p. 541-546.

Research output: Contribution to journalArticle

Bozzola, M, Radetti, G, Buzi, F, Tonini, G, Moretta, A, Autelli, M, Aglialoro, A, Rondini, G & Barreca, A 1999, 'Growth hormone bioactivity and immunoactivity in tall children', Journal of Endocrinological Investigation, vol. 22, no. 7, pp. 541-546.
Bozzola, Mauro ; Radetti, G. ; Buzi, F. ; Tonini, G. ; Moretta, A. ; Autelli, M. ; Aglialoro, A. ; Rondini, G. ; Barreca, A. / Growth hormone bioactivity and immunoactivity in tall children. In: Journal of Endocrinological Investigation. 1999 ; Vol. 22, No. 7. pp. 541-546.
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AU - Tonini, G.

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AU - Autelli, M.

AU - Aglialoro, A.

AU - Rondini, G.

AU - Barreca, A.

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N2 - In subjects with constitutional tall stature, both low and high GH response to stimulation tests have been observed when measured by commercial kits. To investigate the reason for these conflicting results, we evaluated growth hormone (GH) secretion using different assays as well as GH-binding protein and insulin-like growth factor-I (IGF-I) concentrations in tall children. Serum samples were collected from 22 prepubertal constitutionally tall children, aged 2.87-13.25 years, during two pharmacological tests to evaluate serum GH levels measured by both immunofluorometric assay (IFMA) and the Nb2 cell bioassay. Serum IGF-I values were evaluated by RIA. Circulating low affinity (LA) and high affinity (HA) GH-binding proteins (GHBPs) were evaluated by FPLC gel filtration. Considering the highest serum GH levels as measured by IFMA, the 22 tall subjects were divided into two groups: group A including 16 children with blunted serum GH peak levels (5.78 ± 0.68 ng/ml) and group B including 6 subjects with normal serum GH peak values (15.73 ± 1.56 ng/ml). No differences were observed in serum GH peak levels as measured by the Nb2 cell bioassay between group A (14.77 ± 1.54 ng/ml) and group B (16.03 ± 1.96 ng/ml), and between both groups and 11 age-and sex-matched controls (12.25 ± 1.19 ng/ml). In group A, the Nb2 cell bioassay/IFMA ratio of serum GH peak levels (0.29 ± 0.08) was significantly higher (p <0.05) than in group B (0.07 ± 0.01). No differences were found in serum LA-GHBP and HA-GHBP as well as in IGF-I concentrations between the 16 patients of group A and the 6 of group B. Likewise, no difference in auxological parameters was found between the two groups. The biological activity of GH evaluated using the Nb2 cell bioassay is similar in tall children with a low GH response as measured by IFMA in comparison with those with a normal GH response, and is in agreement with both the auxological data and serum IGF-I concentrations.

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