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Multiple component analysis of plasma growth hormone in children with standard and short stature
D E Ayala1, R C Hermida, L Garcia
1ETSI Telecommunicación, Univ. Vigo, Spain.
Insights
Growth hormone (GH) levels show similar daily rhythms in short and average-stature children. However, short children exhibit a distinct 8-hour ultradian rhythm, crucial for time-specific treatment considerations.
Area of Science:
- Chronobiology
- Pediatric Endocrinology
- Hormone Research
Background:
- Growth hormone (GH) secretion patterns are complex and influenced by circadian and ultradian rhythms.
- Understanding these patterns is essential for diagnosing growth disorders and optimizing treatment in children.
Purpose of the Study:
- To compare the circadian and ultradian components of growth hormone secretion in children of short stature versus those of standard stature.
- To investigate potential differences in temporal secretion patterns that may inform treatment strategies.
Main Methods:
- Radioimmunoassay was used to measure plasma GH concentrations at 3-hour intervals over 24 hours.
- Data from 42 boys and 12 girls of short stature and 13 boys and 9 girls of standard stature were analyzed.
- Single and population-mean cosinor methods, analysis of variance, and multiple component analysis were employed.
Main Results:
- Both short and standard stature children displayed prominent circadian and ultradian rhythm components in GH secretion.
- Circadian parameters (mean, amplitude, acrophase) were similar between short and standard stature groups for both boys and girls.
- A significant 8-hour ultradian component was identified in short stature children, but not in standard stature children.
Conclusions:
- While daily GH secretion rhythms are comparable between short and standard stature children, distinct ultradian patterns exist in short children.
- The identified 8-hour ultradian rhythm in short stature children warrants consideration in the timing and design of GH therapy.
- Further research into these temporal secretion differences may lead to more effective, time-specific treatments for children with short stature.
Abstract:
Growth hormone (GH) concentrations (in ng/ml) were determined by radioimmunoassay, in plasma obtained at about 3-hr intervals during a 24-hr sampling span, from 42 boys and 12 girls of short stature (2-4 standard deviations below their peer group mean), and 13 boys and 9 girls of standard stature. Subjects had 11.20 +/- 0.37 years of age at the time of study, and were living on a diurnal waking (approximately 07:30 to approximately 22:30), nocturnal resting routine during sampling. Analysis of these data by single and population-mean cosinor methods as well as by analysis of variance revealed circadian and ultradian prominent components characterizing most groups. Accordingly, a multiple component analysis was undertaken for data of each group separately, as well as for all subjects. A comparison of circadian parameters indicates similar characteristics between short and standard children, whether one compares boys [P = 0.674, 0.371 and 0.749 for comparison of rhythm adjusted means (M), amplitudes (A) and acrophases (phi), respectively], girls (P = 0.993, 0.914 and 0.397), or all children (P = 0.859, 0.712 and 0.865). Differences are found, however, in circasemidian characteristics as well as in the prominent 8-hr ultradian component documented for the short but not for the standard children. These ultradian components should be taken into consideration in the design and later evaluation of a time-specified treatment of children of short stature.