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Spontaneous 24-hour growth hormone profiles in prepubertal small for gestational age children
M Boguszewski1, S Rosberg, K Albertsson-Wikland
1Department of Pediatrics, University of Goteborg, Sweden.
Insights
Children born small for gestational age (SGA) and remaining short secrete less growth hormone (GH) than healthy short children. This reduced GH secretion may contribute to growth failure in SGA children.
Area of Science:
- Pediatric Endocrinology
- Growth Hormone Secretion Dynamics
- Child Development and Growth
Background:
- Children born small for gestational age (SGA) often experience persistent short stature.
- Understanding spontaneous growth hormone (GH) secretion is crucial for evaluating growth failure in SGA children.
- Previous studies have not fully characterized the pulsatile GH secretion patterns in prepubertal SGA children.
Purpose of the Study:
- To evaluate spontaneous GH secretion, including secretory rate and pulsatile pattern, in prepubertal children born SGA and remaining short.
- To compare GH secretion in SGA children with reference groups of short children born appropriate for gestational age (AGA) and children of normal stature.
- To investigate potential correlations between GH secretion parameters and anthropometric measures in SGA children.
Main Methods:
- Investigated 24-hour GH profiles in 106 prepubertal children born SGA and short (below -2 SD scores).
- Utilized deconvolution technique to transform plasma GH concentrations into GH secretion rates.
- Employed Fourier time-series analyses to assess GH secretion rhythmicity and peak characteristics.
Main Results:
- Mean GH secretion rate was significantly lower in SGA children (0.3 U/24 h) compared to short AGA children (0.5 U/24 h) and normal stature children (0.7 U/24 h).
- GH secretion rate correlated positively with weight-for-height SD score in SGA girls, but inversely in short AGA girls.
- Youngest SGA children (2-6 years) exhibited a distinct GH secretion pattern: high basal GH, low peak amplitude, and high peak frequency.
Conclusions:
- Prepubertal children born SGA and remaining short exhibit reduced spontaneous GH secretion compared to healthy short children born AGA.
- This diminished GH secretion may partially explain the growth failure observed in SGA children.
- A unique GH secretion pattern in the youngest SGA children suggests age-specific regulatory mechanisms influencing growth.
Abstract:
To evaluate spontaneous GH secretion in terms of both secretory rate and pulsatile pattern in prepubertal children born small for gestational age (SGA) and still short (below -2 SD scores) at or after 2 yr of age, 24-h GH profiles were investigated in 106 such patients (75 boys and 31 girls; mean age, 7.3 +/- 0.3 yr), 14 of whom (10 boys and 4 girls) had Silver-Russell syndrome. The 24-h secretion of GH was compared with that in 2 reference populations of prepubertal children born at an appropriate size for gestational age (AGA): 179 short healthy children (143 boys and 36 girls; mean age, 10.2 +/- 0.2 yr) and 73 children of normal stature (54 boys and 19 girls; mean age, 10.4 +/- 0.3 yr). Plasma GH concentrations from the 24-h profiles were transformed to GH secretion rates by means of a deconvolution technique. For the SGA children, the mean GH secretion rate was 0.3 U/24 h, with a positive correlation with age, whereas for the reference groups it was higher, 0.5 U/24 h for the short children (P < 0.05) and 0.7 U/24 h for the children of normal stature (P < 0.001). Interestingly, the GH secretion rate correlated positively with weight for height, expressed as the SD score, in girls born SGA (r = 0.40; P < 0.05), whereas an inverse correlation was found for the short AGA girls (r = -0.44; P < 0.05). The mean baseline GH level in the SGA children correlated negatively with age (r = -0.53; P < 0.01), with the highest values found for children younger than 6 yr of age. On the average, 8 GH peaks/24-h period were found in all groups of children, and using Fourier time-series analyses, a similar rhythmicity was found in all groups. In the SGA group, the children younger than 6 yr of age had more GH peaks with lower amplitudes than the older children. It is concluded that children born SGA and still short at or after 2 yr of age spontaneously secrete less GH than healthy children of short stature born AGA. Both of these subgroups of prepubertal short children, however, secrete less GH than children of normal height. This finding might in part explain the growth failure in SGA children. Moreover, in the youngest SGA children (2-6 yr of age) there was another pattern of GH secretion, with a high basal GH level, a low peak amplitude, and a high peak frequency.(ABSTRACT TRUNCATED AT 400 WORDS)